Pyrazine derivative, and light emitting element, display device, electronic device using the pyrazine derivative

ABSTRACT

It is an object to provide a novel material having a bipolar property, a light emitting element provided with the novel material, and a display device that includes the light emitting element. It is an object to provide a pyrazine derivative represented by the following general formula (g-1).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pyrazine derivative. The presentinvention also relates to a light emitting element containing thepyrazine derivative and a display device that includes a light emittingelement containing the pyrazine derivative.

2. Description of the Related Art

In recent years, a light emitting element using a light emittingcompound has been attracted attention as a display (a display device) ofthe next generation because it has a feature of low power consumptionand a lightweight and thin type. In addition, the light emitting elementusing a light emitting compound is a self-luminous type; accordingly, itis considered that the light emitting element using a light emittingcompound has superiority in visibility without problems such as aviewing angle as compared with a liquid crystal display (an LCD).

A basic structure of a light emitting element is a structure that has alight emitting layer containing a light emitting compound interposedbetween a pair of electrodes. It is said that, in such a light emittingelement, by applying a voltage, holes injected from an anode andelectrons injected from a cathode are recombined in an emission centerof a light emitting layer to excite a molecule, and the excited moleculedischarge energy in returning to a ground state; accordingly light isemitted. It is to be noted that an excited state that is generated byrecombination has a singlet excited state and a triplet excited state.Light emission is considered to be possible through a singlet excitedstate and a triplet excited state. In particular, light emission in acase of returning from the singlet excited state to the ground statedirectly is defined as fluorescence, and light emission in a case ofreturning from the triplet excited state to the ground state is definedas phosphorescence.

It is considered that the singlet excited state and the triplet excitedstate, which are an excited state, are generated at a ratio of 1:3statistically. Accordingly, when phosphorescence that is light emissionin a case of returning from the triplet excited state to the groundstate is used, it is theoretically considered that a light emittingelement having internal quantum efficiency (a ratio of photon that isgenerated with respect to injected carriers) of 75 to 100% can beobtained. That is to say, if phosphorescence can be utilized, lightemitting efficiency can be remarkably improved as compared withutilizing fluorescence.

However, phosphorescence can not be observed at a room temperature in ageneral organic compound. This is because that the ground state of anorganic compound is ordinarily in the singlet ground state, andtransition from the triplet excited state to the singlet ground statebecomes forbidden transition. On the other hand, transition from thesinglet excited state to the singlet ground state becomes allowedtransition, and therefore, fluorescence can be observed. However, inrecent years, a compound capable of emitting phosphorescence, in otherwords, a compound capable of converting light in returning from thetriplet excited state to the ground state into light emission(hereinafter, referred to as a phosphorescent compound) is discovered asshown in Patent Document 1, and it has been actively researched (forexample, see Patent Document 1: Japanese Published Patent ApplicationNo. 2005-170851).

When a light emitting element is manufactured using a phosphorescentcompound, the phosphorescent compound is used in a state where thephosphorescent compound is dispersed in a host material in order toprevent decrease of light emitting efficiency due to concentrationquenching. Therefore, in order to efficiently obtain light emission fromthe phosphorescent compound, selection of the host material becomesimportant.

In order to efficiently obtain light emission from the phosphorescentcompound, it is found that a host material having a bipolar property issuitable. However, many of organic compounds are a material having amonopolar property, which has either a hole transporting property or anelectron transporting property. Therefore, a material having a bipolarproperty, which has both the hole transporting property and the electrontransporting property, is required to be developed.

SUMMARY OF THE INVENTION

Consequently, it is an object of the present invention to provide anovel material having a bipolar property, a light emitting elementprovided with the novel material, and a display device that includes thelight emitting element.

In addition, it is also an object of the present invention to provide anovel material having a bipolar property, which can be used as a hostmaterial for dispersing a light emitting compound. In particular, it isan object of the present invention to provide a novel material having abipolar property, which can be used as a host material for dispersing aphosphorescent compound.

Moreover, it is an object of the present invention to provide a novelmaterial having a bipolar property, which can be used as a lightemitting compound.

One aspect of the present invention is a pyrazine derivative representedby the following general formula (g-1).

In the above general formula (g-1), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Further, A in the formula represents asubstituent represented by any of a general formula (a-1), a generalformula (a-2), a general formula (a-3), and a general formula (a-4). R⁴in the formula represents an alkyl group having greater than or equal to1 and less than or equal to 4 carbon atoms or an aryl group havinggreater than or equal to 6 and less than or equal to 25 carbon atoms.Each of R⁵, R⁶, and R⁷ may be same or different, and represents any of ahydrogen atom, an alkyl group having greater than or equal to 1 and lessthan or equal to 4 carbon atoms, and an aryl group having greater thanor equal to 6 and less than or equal to 25 carbon atoms. Each of Ar¹,Ar², Ar³, Ar⁴, Ar⁵, Ar⁶, and Ar⁷ may be same or different, andrepresents an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Further, a represents an arylene grouphaving greater than or equal to 6 and less than equal to 25 carbonatoms. It is to be noted that the aryl group may have a substituent orbe unsubstituted. Further, the arylene group may have a substituent orbe unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-2).

In the above general formula (g-2), each or R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Further, A in the formula represents a substituentrepresented by any of a general formula (a-1), a general formula (a-2),a general formula (a-3), and a general formula (a-4). R⁴ in the formularepresents an alkyl group having greater than or equal to 1 and lessthan or equal to 4 carbon atoms or an aryl group having greater than orequal to 6 and less than or equal to 25 carbon atoms. Each of R⁵, R⁶,and R⁷ may be same or different, and represents any of a hydrogen atom,an alkyl group having greater than or equal to 1 and less than or equalto 4 carbon atoms, and an aryl group having greater than or equal to 6and less than or equal to 25 carbon atoms. Each of Ar¹, Ar², Ar³, Ar⁴,Ar⁵, Ar⁶, and Ar⁷ in the formula may be same or different, andrepresents an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Further, a represents an arylene grouphaving greater than or equal to 6 and less than equal to 25 carbonatoms. It is to be noted that the aryl group may have a substituent orbe unsubstituted. Further, the arylene group may have a substituent orbe unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-3).

In the above general formula (g-3), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. It is to be noted that the aryl group mayhave a substitute and be unsubstituted. Further, each of Ar¹ and Ar² maybe same or different, and represents any of a phenyl group, a 1-naphthylgroup, a 2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a4-biphenyl group, a 9,9-dimethylfluorene-2-yl group, and aspiro-9,9′-bifluorene-2-yl group.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-4).

In the above formula (g-4), each or R¹, R², and R³ may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Further, each of Ar³, Ar⁴, and Ar⁵ may be same ordifferent, and represents an aryl group having greater than or equal to6 and less than or equal to 25 carbon atoms. It is to be noted that thearyl group may have a substituent or be unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-5).

In the above general formula (g-5), each or R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Further, Ar³ represents an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. It is to be noted that the aryl group may have a substitutent orbe unsubstituted.

Furthermore, in the above general formula (g-5), the Ar³ is preferablyany of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-6).

In the above general formula (g-6), each or R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. R⁴ represents an alkyl group having greaterthan or equal to 1 and less than or equal to 4 carbon atoms or an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. Ar⁶ represents any of a phenyl group, a 1-naphthyl group,a 2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenylgroup, a 9,9-dimethylfluorene-2-yl group, and aspiro-9,9′-bifluorene-2-yl group. It is to be noted that the aryl groupmay have a substituent or be unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-7).

In the above general formula (g-7), each or R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Each of R⁶ and R⁷ may be same or different,and represents any of a hydrogen atom, an alkyl group having greaterthan or equal to 1 and less than or equal to 4 carbon atoms, and an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. Ar⁷ represents an aryl group having greater than or equalto 6 and less than or equal to 25 carbon atoms. It is to be noted thatthe aryl group may have a substituent or be unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-8).

In the above general formula (g-8), each or R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Each of R⁶ and R⁷ may be same or different,and represents any of a hydrogen atom, an alkyl group having greaterthan or equal to 1 and less than or equal to 4 carbon atoms, and an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. Ar⁷ represents an aryl group. It is to be noted that thearyl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-8), Ar⁷ is preferably any of aphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenylgroup, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-9).

In the above general formula (g-9), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of Ar¹ and Ar² may be same or different, andrepresents any of a phenyl group, a 1-naphthyl group, a 2-naphthylgroup, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group.It is to be noted that the aryl group may have a substituent or beunsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-10).

In the above general formula (g-10), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of Ar³, Ar⁴, and Ar⁵ may be same or different,and represents an aryl group having greater than or equal to 6 and lessthan or equal to 25 carbon atoms. It is to be noted that the aryl groupmay have a substituent or be unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-11).

In the above general formula (g-11), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Ar³ represents an aryl group having greater than orequal to 6 and less than or equal to 25 carbon atoms. It is to be notedthat the aryl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-11), Ar³ is preferably any of aphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenylgroup, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group.

Another aspect of the present invention is a pyrazine derivativerepresented by the general formula (g-12).

In the above general formula (g-12), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. R⁴ represents an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms or an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. Ar⁶ represents any of a phenyl group, a 1-naphthyl group, a2-naphthyl group, a 2-biphenyl group, a 3-biphenyl group, a 4-biphenylgroup, a 9,9-dimethylfluorene-2-yl group, and aspiro-9,9′-bifluorene-2-yl group. It is to be noted that the aryl groupmay have a substituent or be unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-13).

In the above general formula (g-13), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of R⁶ and R⁷ may be same or different, andrepresents any of a hydrogen atom, an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms, and an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. Ar⁷ represents an aryl group having greater than or equal to 6and less than equal to 25 carbon atoms. It is to be noted that the arylgroup may have a substituent or be unsubstituted.

Another aspect of the present invention is a pyrazine derivativerepresented by the following general formula (g-14).

In the above general formula (g-14), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of R⁶ and R⁷ may be same or different, andrepresents any of a hydrogen atom, an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms, and an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. Ar⁷ represents an aryl group having greater than or equal to 6and less than equal to 25 carbon atoms. It is to be noted that the arylgroup may have a substituent or be unsubstituted.

Further, in the above general formula, Ar⁷ is preferably any of a phenylgroup, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenyl group, a3-biphenyl group, a 4-biphenyl group, a 9,9-dimethylfluorene-2-yl group,and a spiro-9,9′-bifluorene-2-yl group.

Another aspect of the present invention is a light emitting element thatincludes a layer containing a pyrazine derivative described in any oneof the above general formulas (g-1) to (g-14) between a pair ofelectrodes.

Another aspect of the present invention is a light emitting element thatincludes a layer containing a pyrazine derivative described in any oneof the above general formulas (g-1) to (g-14) and a light emittingcompound between a pair of electrodes.

Another aspect of the present invention is a light emitting element thatincludes a layer containing a pyrazine derivative described in any oneof the above general formulas (g-1) to (g-14) and a phosphorescentcompound between a pair of electrodes. It is to be noted that thephosphorescent compound indicates a compound capable of dischargingphosphorescence, in other words, a compound capable of converting lightthat is emitted in returning from a triplet excited state to a groundstate into light emission.

Another aspect of the present invention is a display device thatincludes a light emitting element containing a pyrazine derivativedescribed in any one of the above general formulas (g-1) to (g-14).

Another aspect of the present invention is a display device thatincludes a light emitting element containing a pyrazine derivativedescribed in any one of the above general formulas (g-1) to (g-14) and aphosphorescent compound.

Another aspect of the present invention is an electronic device thatincludes a light emitting element containing a pyrazine derivativedescribed in any one of the above general formulas (g-1) to (g-14).

Another aspect of the present invention is an electronic device thatincludes a light emitting element containing a pyrazine derivativedescribed in any one of the above general formulas (g-1) to (g-14) and aphosphorescent compound.

A pyrazine derivative of the present invention is a pyrazine derivativehaving a bipolar property and superiority in both an electrontransporting property and a hole transporting property.

A pyrazine derivative of the present invention is a pyrazine derivativethat is stable to electrochemical oxidization or reduction.

A pyrazine derivative of the present invention is a light emittingcompound having a bipolar property and superiority in both an electrontransporting property and a hole transporting property.

By dispersing a phosphorescent compound in a layer made of a pyrazinederivative of the present invention, a light emitting element havingextremely high light emitting efficiency can be obtained.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view showing an example of a light emitting element of thepresent invention.

FIG. 2 is a view showing an example of a light emitting element of thepresent invention.

FIGS. 3A and 3B are views each showing an example of a display device ofthe present invention.

FIG. 4 is a top view showing an example of a pixel portion in a displaydevice of the present invention.

FIG. 5 is a circuit diagram showing an example of a pixel portion in adisplay device of the present invention.

FIGS. 6A and 6B are views each showing an example of a display device ofthe present invention.

FIGS. 7A and 7B are views each showing an example of a panel providedwith a display device of the present invention.

FIG. 8 is a view showing an example of an electronic device of thepresent invention.

FIGS. 9A to 9D are views each showing an example of an electronic deviceof the present invention.

FIGS. 10A and 10B are ¹H-NMR charts of BBAPPr.

FIG. 11 is a graph showing an absorption spectrum and an emissionspectrum in a state where BBAPPr is dissolved in a toluene solution.

FIGS. 12A and 12B are graphs showing a measurement result by cyclicvoltammetry (CV) of BBAPPr.

FIGS. 13A and 13B are ¹H-NMR charts of BBhAPPr.

FIG. 14 is a graph showing an absorption spectrum and an emissionspectrum in a state where BBhAPPr is dissolved in a toluene solution.

FIG. 15 is a graph showing an absorption spectrum and an emissionspectrum in a single film state of BPhAPPr. FIGS. 16A and 16B are ¹H-NMRcharts of DPhAPPr.

FIG. 17 is a graph showing an absorption spectrum and an emissionspectrum in a state where DPhAPPr is dissolved in a toluene solution.

FIG. 18 is a graph showing an absorption spectrum and an emissionspectrum in a single film state of DPhAPPR.

FIGS. 19A and 19B are ¹H-NMR charts of DPAPPr.

FIG. 20 is a graph showing an absorption spectrum and an emissionspectrum in a state where DPAPPr is dissolved in a toluene solution.

FIGS. 21A and 21B are ¹H-NMR charts of PCAPPr.

FIG. 22 is a graph showing an absorption spectrum and an emissionspectrum in a state where PCAPPr is dissolved in a toluene solution.

FIG. 23 is a graph showing an absorption spectrum and an emissionspectrum in a single film state of PCAPPr.

FIGS. 24A and 24B are ¹H-NMR charts of YGAPPr.

FIG. 25 is a graph showing an absorption spectrum and an emissionspectrum in a state where YGAPPr is dissolved in a toluene solution.

FIG. 26 is a graph showing an absorption spectrum and an emissionspectrum in a single film state of YGAPPr.

FIG. 27 is a view showing an example of a light emitting element ofEmbodiment 7.

FIG. 28 is a graph showing a current density-luminance characteristic ofa light emitting element of Embodiment 7.

FIG. 29 is a graph showing a voltage-luminance characteristic of a lightemitting element of Embodiment 7.

FIG. 30 is a graph showing a luminance-current efficiency characteristicof a light emitting element of Embodiment 7.

FIG. 31 is a graph showing a luminance-external quantum efficiencycharacteristic of a light emitting element of Embodiment 7.

FIG. 32 is a view showing an example of a light emitting element ofEmbodiment 8.

FIG. 33 is a graph showing a current density-luminance characteristic ofa light emitting element of Embodiment 8.

FIG. 34 is a graph showing a voltage-luminance characteristic of a lightemitting element of Embodiment 8.

FIG. 35 is a graph showing a luminance-current efficiency characteristicof a light emitting element of Embodiment 8.

FIG. 36 is a graph showing a luminance-external quantum efficiencycharacteristic of a light emitting element of Embodiment 8.

FIGS. 37A and 37B are ¹H-NMR charts of DPhAPPPr.

FIG. 38 is a graph showing an absorption spectrum and an emissionspectrum in a state where DPhAPPPr is dissolved in a toluene solution.

FIGS. 39A and 39B are ¹H-NMR charts of YGAPPPr.

FIG. 40 is a graph showing an absorption spectrum and an emissionspectrum in a state where YGAPPPr is dissolved in a toluene solution.

FIG. 41 is a graph showing a current density-luminance characteristic ofa light emitting element of Embodiment 11.

FIG. 42 is a graph showing a voltage-luminance characteristic of a lightemitting element of Embodiment 11.

FIG. 43 is a graph showing a luminance-current efficiency characteristicof a light emitting element of Embodiment 11.

FIG. 44 is a graph showing an emission spectrum of a light emittingelement of Embodiment 11.

FIG. 45 is a graph showing a current density-luminance characteristic ofa light emitting element of Embodiment 12.

FIG. 46 is a graph showing a voltage-luminance characteristic of a lightemitting element of Embodiment 12.

FIG. 47 is a graph showing a luminance-current efficiency characteristicof a light emitting element of Embodiment 12.

FIG. 48 is a graph showing an emission spectrum of a light emittingelement of Embodiment 12.

FIG. 49 is a view showing an example of a light emitting element ofEmbodiment 11.

FIG. 50 is a view showing an example of a light emitting element ofEmbodiment 12.

FIGS. 51A and 51B are ¹H-NMR charts of YGA1PPPr.

FIG. 52 is a graph showing an absorption spectrum and an emissionspectrum in a state where YGA1PPPr is dissolved in a toluene solution.

DETAILED DESCRIPTION OF THE INVENTION

(Embodiment Mode 1)

In this embodiment mode, a pyrazine derivative of the present inventionwill be explained.

A pyrazine derivative of the present invention is represented by thefollowing general formula (g-1).

In the above general formula (g-1), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Further, A in the formula represents asubstitutent represented by any of a general formula (a-1), a generalformula (a-2), a general formula (a-3), and a general formula (a-4). R⁴in the formula represents an alkyl group having greater than or equal to1 and less than or equal to 4 carbon atoms or an aryl group havinggreater than or equal to 6 and less than or equal to 25 carbon atoms.Each of R⁵, R⁶, and R⁷ may be same or different, and represents any of ahydrogen atom, an alkyl group having greater than or equal to 1 and lessthan or equal to 4 carbon atoms, and an aryl group having greater thanor equal to 6 and less than or equal to 25 carbon atoms. Each of Ar¹ toAr⁷ may be same or different, and represents an aryl group havinggreater than or equal to 6 and less than or equal to 25 carbon atoms.Further, a represents an arylene group represents having greater than orequal to 6 and less than or equal to 25 carbon atoms. It is to be notedthat the aryl group in the formula may have a substituent or beunsubstituted. In a similar manner, the arylene group may have asubstituent or be unsubstituted.

Further, in the above general formula (g-1), as a specific example ofthe alkyl group having greater than or equal to 1 and less than or equalto 4 carbon atoms, a methyl group, an ethyl group, an i-propyl group, ann-propyl group, an n-butyl group, a t-butyl group, an i-butyl group, ans-butyl group, or the like can be given. As a specific example of thearyl group having greater than or equal to 6 and less than or equal to25 carbon atoms, a phenyl group, an o-tolyl group, a m-tolyl group, ap-tolyl group, a napthly group, a 2-naphthyl group, a 4-biphenyl group,a 3-biphenyl group, a 2-biphenyl group, a 9,9-methylfluorene-2-yl group,a spiro-9,9′-bifluorene-2-yl group, or the like can be given. As aspecific example of the arylene group having greater than or equal to 6and less than or equal to 25 carbon atoms, an o-phenylene group, am-phenylene group, a p-phenylene group, a 1,5-naphthylene group, a1,4-naphthylene group, a 9,9-dimethylfluorene-2,7-diyl group, a4,4-biphenylene group, a spiro-9,9′-bifluorene-2,7-diyl group, or thelike can be given.

Furthermore, in the above general formula (g-1), when A in the formulais the substituent represented by the general formula (a-1), and Ar¹ andAr² are any of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention. Inother words, the present invention is preferably a pyrazine derivativerepresented by the following general formula (g-3).

In the above general formula (g-3), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. It is to be noted that the aryl group mayhave a substituent or be unsubstituted.

Further, in the above general formula (g-1), when A in the formula isthe substituent represented by the general formula (a-4), and α is aphenylene group, much higher triplet excitation energy can be obtained,and chemical stability can be obtained, which is preferable in thepresent invention. In other words, the present invention is preferably apyrazine derivative represented by the following general formula (g-4).

In the above general formula (g-4), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Each of Ar³, Ar⁴, and Ar⁵ may be same ordifferent, and represents an aryl group having greater than or equal to6 and less than or equal to 25 carbon atoms. It is to be noted that thearyl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-1), when A in the formula isthe substituent represented by the general formula (a-2), Ar⁴ and Ar⁵are a phenyl group, and α is a 1,4-phenylene group, much higher tripletexcitation energy can be obtained, and synthesis becomes easy, which ispreferable in the present invention. In other words, the presentinvention is preferably a pyrazine derivative represented by thefollowing formula (g-5).

In the above general formula (g-5), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Ar³ represents an aryl group having greaterthan or equal to 6 and less than or equal to 25 carbon atoms. It is tobe noted that the aryl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-5), when Ar³ in the formula isany of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention.

Furthermore, in the above general formula (g-1), when A in the formulais the substituent represented by the general formula (a-3), and Ar⁶ isany of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention. Inother words, the present invention is preferably a pyrazine derivativerepresented by the following general formula (g-6).

In the above general formula (g-6), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. R⁴ represents an alkyl group having greaterthan or equal to 1 and less than or equal to 4 carbon atoms or an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. It is to be noted that the aryl group may have asubstituent or be unsubstituted.

Further, in the above general formula (g-1), when A in the formula isthe substituent represented by the general formula (a-4), and α is aphenylene group, much higher triplet excitation energy can be obtained,and chemical stability can be obtained, which is preferable in thepresent invention. In other words, the present invention is preferably apyrazine derivative represented by the following general formula (g-7).

In the above general formula (g-7), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Each of R⁶ and R⁷ may be same or different,and represents any of a hydrogen atom, an alkyl group having greaterthan or equal to 1 and less than or equal to 4 carbon atoms, and an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. Ar⁷ represents an aryl group having greater than or equalto 6 and less than or equal to 25 carbon atoms. It is to be noted thatthe aryl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-1), when A in the formula isthe substituent represented by the general formula (a-4), and α is a1,4-phenylene group, much higher triplet excitation energy can beobtained, and chemical stability can be obtained, which is preferable inthe present invention. In other words, the present invention ispreferably a pyrazine derivative represented by the following generalformula (g-8).

In the above general formula (g-8), each of R¹, R², and R³ may be sameor different, and represents any of a hydrogen atom, an alkyl grouphaving greater than or equal to 1 and less than or equal to 4 carbonatoms, and an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Each of R⁶ and R⁷ may be same or different,and represents any of a hydrogen atom, an alkyl group having greaterthan or equal to 1 and less than or equal to 4 carbon atoms, and an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. Ar⁷ represents an aryl group. It is to be noted that thearyl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-8), when Ar⁷ in the formula isany of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention.

In addition, a pyrazine derivative of the present invention isrepresented by the following general formula (g-2).

In the above general formula (g-2), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. It is to be noted that the aryl group in the formulamay have a substituent or be unsubstituted. Further, A in the formularepresents a substituent represented by any of a general formula (a-1),a general formula (a-2), a general formula (a-3), and a general formula(a-4). R⁴ in the formula represents an alkyl group having greater thanor equal to 1 and less than or equal to 4 carbon atoms or an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. Each of R⁵, R⁶, and R⁷ may be same or different, and representsany of a hydrogen atom, an alkyl group having greater than or equal to 1and less than or equal to 4 carbon atoms, and an aryl group havinggreater than or equal to 6 and less than or equal to 25 carbon atoms. Itis to be noted that the aryl group may have a substituent or beunsubstituted. Each of Ar¹ to Ar⁷ in the formula may be same ordifferent, and represents an aryl group having greater than or equal to6 and less than or equal to 25 carbon atoms. Further, a represents anarylene group having greater than or equal to 6 and less than or equalto 25 carbon atoms. It is to be noted that the arylene group may have asubstituent or be unsubstituted.

Further, in the above general formula (g-2), as a specific example ofthe alkyl group having greater than or equal to 1 and less than or equalto 4 carbon atoms, a methyl group, an ethyl group, an i-propyl group, ann-propyl group, an n-butyl group, a t-butyl group, an i-butyl group, ans-butyl group, or the like can be given. As a specific example of thearyl group having greater than or equal to 6 and less than or equal to25 carbon atoms, a phenyl group, an o-tolyl group, a m-tolyl group, ap-tolyl group, a napthly group, a 2-naphthyl group, a 4-biphenyl group,a 3-biphenyl group, a 2-biphenyl group, a 9,9-methylfluorene-2-yl group,a spiro-9,9′-bifluorene-2-yl group, or the like can be given. As aspecific example of the arylene group having greater than or equal to 6and less than or equal to 25 carbon atoms, an o-phenylene group, am-phenylene group, a p-phenylene group, a 1,5-naphthylene group, a1,4-naphthylene group, a 9,9-dimethylfluorene-2,7-diyl group, a4,4-biphenylene group, a spiro-9,9′-bifluorene-2,7-diyl group, or thelike can be given.

Furthermore, in the above general formula (g-2), when A in the formulais the substituent represented by the general formula (a-1), and Ar¹ andAr² are any of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention. Inother words, the present invention is preferably a pyrazine derivativerepresented by the following general formula (g-9).

In the above general formula (g-9), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. It is to be noted that the aryl group may have asubstituent or be unsubstituted.

Further, in the above general formula (g-2), when A in the formula isthe substituent represented by the general formula (a-2), and α is aphenylene group, much higher triplet excitation energy can be obtained,and chemical stability can be obtained, which is preferable in thepresent invention. In other words, the present invention is preferably apyrazine derivative represented by the following general formula (g-10).

In the above general formula (g-10), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of Ar³, Ar⁴, and Ar⁵ may be same or different,and represents an aryl group having greater than or equal to 6 and lessthan equal to 25 carbon atoms. It is to be noted that the aryl group mayhave a substituent or be unsubstituted.

Further, in the above general formula (g-2), when A in the formula isthe substituent represented by the general formula (a-2), Ar⁴ and Ar⁵are a phenyl group, and α is a 1,4-phenylene group, much higher tripletexcitation energy can be obtained, and synthesis becomes easy, which ispreferable in the present invention. In other words, the presentinvention is preferably a pyrazie derivative represented by thefollowing general formula (g-11).

In the above general formula (g-11), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Ar³ represents an aryl group having greater than orequal to 6 and less than or equal to 25 carbon atoms. It is to be notedthat the aryl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-11), when Ar³ in the formula isany of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention.

Furthermore, in the above general formula (g-2), when A in the formulais the substituent represented by the general formula (a-3), Ar⁶ is anyof a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenylgroup, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention. Inother words, the present invention is preferably a pyrazine derivativerepresented by the following general formula (g-12).

In the above general formula (g-12), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. R⁴ represents an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms or an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. It is to be noted that the aryl group may have a substituent orbe unsubstituted.

Further, in the above general formula (g-2), when A in the formula isthe substitutent represented by the general formula (a-4), and α is aphenylene group, much higher triplet excitation energy can be obtained,and chemical stability can be obtained, which is preferably in thepresent invention. In other words, the present invention is preferably apyrazine derivative represented by the following general formula (g-13).

In the above general formula (g-13), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of R⁶ and R⁷ may be same or different, andrepresents any of a hydrogen atom, an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms, and an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. Ar⁷ represents an aryl group having greater than or equal to 6and less than or equal to 25 carbon atoms. It is to be noted that thearyl group may have a substituent or be unsubstituted.

Further, in the above general formula (g-2), when A in the formula isthe substituent represented by the general formula (a-4), and α is a1,4-phenylene group, much higher triplet excitation energy can beobtained, and chemical stability can be obtained, which is preferably inthe present invention. In other words, the present invention is apyrazine derivative represented by the following general formula (g-14).

In the above general formula (g-14), each of R¹ and R² may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of R⁶ and R⁷ may be same or different, andrepresents any of a hydrogen atom, an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms, and an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. Ar⁷ represents an aryl group. It is to be noted that the arylgroup may have a substituent or be unsubstituted.

Further, in the above general formula (g-14), when Ar⁷ in the formula isany of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,synthesis becomes easy, which is preferable in the present invention.

As a specific example of a pyrazine derivative of the present invention,pyrazine derivatives represented by structural formulas (s-1) to (s-115)can be given. It is to be noted that a pyrazine derivative of thepresent invention is not limited to the structural formulas below, and adifferent structure from a structure represented by the followingformulas can be employed.

Various reactions can be applied to a synthesis method of a pyrazinederivative of the present invention. For example, a pyrazine derivativecan be formed by performing a synthetic reaction shown in the followingsynthesis scheme (c-1), synthesis scheme (c-2), synthesis scheme (c-3),and synthesis scheme (c-4).

In the above synthesis schemes (c-1) to (c-4), x in the formularepresents a halogen atom. Each of R¹, R², and R³ may be same ordifferent, and represents any of a hydrogen atom, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms, andan aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. It is to be noted that the aryl group may have asubstituent or be unsubstituted. R⁴ represents an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms oran aryl group having greater than or equal to 6 and less than or equalto 25 carbon atoms. Each of R⁵, R⁶, and R⁷ may be same or different, andrepresents any of a hydrogen atom, an alkyl group having greater than orequal to 1 and less than or equal to 4 carbon atoms, and an aryl grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. It is to be noted that the aryl group may have a substituent orbe unsubstituted. Each of Ar¹ to Ar⁷ may be same or different, andrepresents an aryl group having greater than or equal to 6 and less thanor equal to 25 carbon atoms. Further, a represents an arylene grouphaving greater than or equal to 6 and less than or equal to 25 carbonatoms. It is to be noted that the arylene group may have a substituentor be unsubstituted.

In the above synthesis scheme (c-1), coupling reaction of a 1 equivalentsecondary amine compound is performed with respect to a pyrazinederivative halide by using a palladium catalyst or monovalent copper inthe presence of a base, whereby a pyrazine derivative of the presentinvention can be synthesized. As the base, an inorganic base such aspotassium carbonate or sodium carbonate, an organic base such as metalalkoxide, or the like can be used. As the palladium catalyst, palladiumacetate, palladium chloride (II), bis(dibenzylideneacetone)palladium(0),or the like can be used.

In the synthesis scheme (c-2), the synthesis scheme (c-3), and thesynthesis scheme (c-4), a pyrazine derivative of the present inventioncan be synthesized by the similar manner to the synthesis scheme (c-1)as explained above. In other words, in each of the synthesis schemes(c-2) to (c-4), coupling reaction of a 1 equivalent secondary aminecompound is performed with respect to a pyrazine derivative halide byusing a palladium catalyst or monovalent copper in the presence of abase, whereby a pyrazine derivative of the present invention can besynthesized. As the base, an inorganic base such as potassium carbonateor sodium carbonate, an organic base such as a metal alkoxide, or thelike can be used. As the palladium catalyst, palladium acetate,palladium chloride (II), bis(dibenzylideneacetone)palladium(0), or thelike can be used.

Further, a pyrazine derivative of the present invention can bemanufactured, for example, by performing synthetic reaction shown in thefollowing synthesis scheme (d-1), synthesis scheme (d-2), synthesisscheme (d-3), and synthesis scheme (d-4).

In the above synthesis scheme (d-1), synthesis scheme (d-2), synthesisscheme (d-3), and synthesis scheme (d-4), x in the formula represents ahalogen atom. Each of R¹ and R² may be same or different, and representsany of a hydrogen atom, an alkyl group having greater than or equal to 1and less than or equal to 4 carbon atoms, and an aryl group havinggreater than or equal to 6 and less than or equal to 25 carbon atoms. Itis to be noted that the aryl group may have a substituent or beunsubstituted. R⁴ represents an alkyl group having greater than or equalto 1 and less than or equal to 4 carbon atoms or an aryl group havinggreater than or equal to 6 and less than or equal to 25 carbon atoms.Each of R⁵, R⁶, and R⁷ may be same or different, and represents any of ahydrogen atom, an alkyl group having greater than or equal to 1 and lessthan or equal to 4 carbon atoms, and an aryl group having greater thanor equal to 6 and less than or equal to 25 carbon atoms. It is to benoted that the aryl group may have a substituent or be unsubstituted.Each of Ar¹ to Ar⁷ may be same or different, and represents an arylgroup having greater than or equal to 6 and less than or equal to 25carbon atoms. Further, α represents an arylene group having greater thanor equal to 6 and less than or equal to 25 carbon atoms.

In the above synthesis scheme (d-1), coupling reaction of a 2 equivalentsecondary amine compound is performed with respect to a pyrazinederivative halide by using a palladium catalyst or monovalent copper inthe presence of a base, whereby a pyrazine derivative of the presentinvention can be synthesized. As the base, an inorganic base such aspotassium carbonate or sodium carbonate, an organic base such as a metalalkoxide, or the like can be used. As the palladium catalyst, palladiumacetate, palladium chloride (II), bis(dibenzylideneacetone)palladium(0),or the like can be used.

In the synthesis schemes (d-2) to (d-4), a pyrazine derivative of thepresent invention can be synthesized by the similar manner to thesynthesis scheme as explained above. In other words, in each of thesynthesis schemes (d-2) to (d-4), coupling reaction of a 2 equivalentsecondary amine compound is performed with respect to a pyrazinederivative halide by using a palladium catalyst or monovalent copper inthe presence of a base, whereby a pyrazine derivative of the presentinvention can be synthesized. As the base, an inorganic base such aspotassium carbonate or sodium carbonate, an organic base such as a metalalkoxide, or the like can be used. As the palladium catalyst, palladiumacetate, palladium chloride (II), bis(dibenzylideneacetone)palladium(0),or the like can be used.

It is to be noted that a synthesis method of a pyrazine derivative ofthe present invention is not limited to the above method, and a pyrazinederivative may be synthesized by another synthesis method.

The pyrazine derivative of the present invention, which is synthesizedas the above, is a pyrazine derivative having a bipolar property andsuperiority in an electron transporting property and a hole transportingproperty.

Further, a pyrazine derivative of the present invention is a pyrazinederivative that is stable to electrochemical oxidization or reduction.

(Embodiment Mode 2)

In this embodiment mode, one mode of a light emitting element using apyrazine derivative of the present invention will be explained withreference to FIG. 1.

A structure of a light emitting element in this embodiment mode has alight emitting layer between a pair of electrodes (an anode and acathode). A light emitting element of the present invention is providedwith a layer between each electrode and the light emitting layer, whichis made from a substance having a high hole injecting property orelectron injecting property or a substance having a high holetransporting property or electron transporting property. By employingsuch a structure, a light emitting region is formed in a portionseparated from the electrode in the light emitting element of thepresent invention.

In a light emitting element 100 shown in FIG. 1, a light emitting layer104 is provided between a first electrode 101 and a second electrode107. In this embodiment mode, a pyrazine derivative and a phosphorescentcompound of the present invention are contained in the light emittinglayer 104.

The light emitting element 100 of the present invention has a structurein which a hole injecting layer 102 and a hole transporting layer 103are sequentially stacked between the first electrode 101 and the lightemitting layer 104. In addition, the light emitting element 100 of thepresent invention has a structure in which an electron transportinglayer 105 and an electron injecting layer 106 are sequentially stackedbetween the light emitting layer 104 and the second electrode 107. It isto be noted that the element structure is not limited to this, and aknown structure may be appropriately selected depending on the purpose.

In the light emitting element 100 of the present invention, one of thefirst electrode 101 and the second electrode 107 becomes an anode, andthe other becomes a cathode. The anode indicates an electrode forinjecting holes into the light emitting layer, and the cathode indicatesan electrode for injecting electrons into the light emitting layer. Inthis embodiment mode, the first electrode 101 is an anode, and thesecond electrode 107 is a cathode. Hereinafter, the light emittingelement 100 of the present invention will be specifically explained.

As the first electrode 101 (anode), a metal, an alloy, a conductivecompound, or a mixture thereof, each of which has a high work function(specifically, 4.0 eV or more), or the like is preferably used.Specifically, a transparent conductive film made from a conductivematerial having a light transmitting property may be used. For example,indium tin oxide (ITO), indium silicon tin oxide to which silicon oxideis added (ITSO), indium zinc oxide (IZO), or the like can be used. Inaddition, a metal material such as gold (Au), platinum (Pt), nickel(Ni), tungsten (W), chromium (Cr), zinc (Zn), tin (Sn), indium (In),molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), or palladium (Pd)may be used. Further, a nitride of a metal material (such as titaniumnitride (TiN)) may be used. The first electrode 101 may be formed of asingle layer or a stacked layer of two or more layers of these materialswith the use of a sputtering method, an evaporation method, or the like.Moreover, the first electrode 101 may be formed by applying a sol-gelmethod.

As the hole injecting layer 102, molybdenum oxide (MoOx), vanadium oxide(VOx), ruthenium oxide (RuOx), tungsten oxide (WOx), manganese oxide(MnOx), or the like can be used. In addition, it is possible to use aphthalocyanine-based compound such as phthalocyanine (H₂Pc) or copperphthalocyanine (CuPc), a high molecule such as poly(ethylenedioxythiophene)/poly(styrenesulfonic acid) (PEDOT/PSS), or the like.

Alternatively, as the hole injecting layer 102, a composite materialincluding an organic compound and an inorganic compound may be used. Asfor the inorganic compound included in the composite material, asubstance having an electron-accepting property to the organic compoundmay be used, and specifically, oxide of a transition metal is preferablyused. For example, a metal oxide such as titanium oxide (TiO_(x)),vanadium oxide (VO_(x)), molybdenum oxide (MoO_(x)), tungsten oxide(WO_(x)), rhenium oxide (ReO_(x)), ruthenium oxide (RuO_(x)), chromiumoxide (CrO_(x)), zirconium oxide (ZrO_(x)), hafnium oxide (HfO_(x)),tantalum oxide (TaO_(x)), silver oxide (AgO_(x)), or manganese oxide(MnO_(x)) can be used. As for the organic compound, a material excellentin a hole transporting property is preferably used. Specifically, anaromatic amine-based organic compound or a carbazole-based organiccompound can be used. Alternatively, aromatic hydrocarbon-based organiccompound may be used. The composite material including an organiccompound and an inorganic compound having an electron-accepting propertyto the organic compound as the above has superiority in a hole injectingproperty and a hole transporting property, because carrier density isincreased by supplying and accepting electrons between the organiccompound and the inorganic compound. Further, by using such a compositematerial including an organic compound and an inorganic compound havingan electron-accepting property to the organic compound as the holeinjecting layer 102, ohmic contact between the first electrode 101 andthe hole injecting layer 102 becomes possible. As a result, a materialfor forming the first electrode 101 can be selected regardless of highand low of the work function.

By providing the hole injecting layer 102 to be in contact with thefirst electrode 101 as the present invention, a hole injecting barriercan be reduced. As a result, a driving voltage of the light emittingelement 100 can be reduced.

As the hole transporting layer 103, a substance having a high holetransporting property can be used. Specifically, an aromatic amine-based(that is, one having a bond of benzene ring-nitrogen) compound ispreferably used. For example, the following substance can be used:4,4′-bis[N-(3-methylphenyl)-N-phenylamino]biphenyl, derivatives thereofsuch as 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (hereinafterreferred to as NPB), or a star burst aromatic amine compound such as4,4′,4″-tris(N,N-diphenyl-amino)triphenylamine, or4,4′,4″-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine. Thesubstances described here are a substance mainly having the holemobility of 10⁻⁶ cm²/Vs or more. However, the present invention is notlimited to this, and another substance may be used as long as it has ahigher hole transporting property than an electron transportingproperty. It is to be noted that the hole transporting layer 103 may beformed of a single layer, a mixed layer, or a stacked layer of two ormore layers of these materials.

As the light emitting layer 104, a layer containing a pyrazinederivative that is represented by any of the above general formulas(g-1) to (g-14) and a light emitting compound of the present inventionis used. Specifically, a light emitting compound is dispersed in a layermade from a pyrazine derivative of the present invention. That is, thepyrazine derivative of the present invention is to be a host material,and the light emitting compound is to be a guest material. By employingsuch a structure, light emission from the light emitting compound thatis the guest material can be obtained, and a light emission color due tothe light emitting compound can be obtained. Further, the pyrazinederivative of the present invention serves as a light emittingsubstance; therefore, a light emission color in which a light emissioncolor due to the light emitting compound and a light emission color dueto the pyrazine derivative of the present invention are mixed can beobtained.

As the light emitting compound contained in the light emitting layer104, a fluorescent compound and a phosphorescent compound can be used.Specifically, a fluorescent compound such as4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran(abbreviated to DCM1),4-(dicyanomethylene)-2-methyl-6-(julolidine-4-yl-vinyl)-4H-pyran(abbreviated to DCM2), N,N′-dimethylquinacridone (abbreviated to DMQd),9,10-diphenylanthracene (abbreviated to DPA), 5,12-diphenyltetracene(abbreviated to DPT), coumarin 6, perylene, or rubrene can be used.

As the phosphorescent compound, a metal complex mainly containing atransition metal such as iridium (Ir) or platinum (Pt), or the like canbe used, such asbis(2-phenylbenzothiazolato-N,C^(2′))iridium(III)acetylacetonate(abbreviated to Ir(bt)₂(acac)),tris(2-phenylquinolinato-N,C²′)iridium(III) (abbreviated to Ir(pa)₃),bis(2-phenylquinolinato-N,C²′)iridium(III)acetylacetonate (abbreviatedto Tr(pq)₂(acac)),bis[2-(2′-benzo[4,5-a]thienyl)pyridinato-N,C^(3′)]iridium(III)acetylacetonate(abbreviated to Ir(btp)₂(acac)),bis(1-phenylisoquinolinato-N,C²′)iridium(III)acetylacetonate(abbreviated to Ir(piq)₂(acac)),(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(abbreviated to Ir(Fdpq)₂(acac)), or2,3,7,8,12,13,17,18-octaetyl-21H,23H-porphyrinplatinum(II) (abbreviatedto PtOEP).

As the electron transporting layer 105, a substance having a highelectron transporting property can be used. For example, it is possibleto use a metal complex having a quinoline skeleton or a benzoquinolineskeleton or the like, such as tris(8-quinolinolato)aluminum (abbreviatedto Alq₃), tris(4-methyl-8-quinolinolato)aluminum (abbreviated to Almq₃),bis(10-hydroxybenzo[h]-quinolinato)beryllium (abbreviated to BeBq₂), orbis(2-methyl-8-quinolinolato)-4-phenylphenolato-aluminum (abbreviated toBAlq). Alternatively, a metal complex having an oxazole-based or athiazole-based ligand, such asbis[2-(2-hydroxyphenyl)-benzoxazolato]zinc (abbreviated to Zn(BOX)₂) orbis[2-(2-hydroxyphenyl)-benzothiazolato]zinc (abbreviated to Zn(BTZ)₂)can be used. Further, other than the metal complexes,2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated toPBD), 1,3-bis[5-(p-tert-buthylphenyl)-1,3,4-oxadiazol-2-yl]benzene(abbreviated to OXD-7),3-(4-tert-butylphenyl)-4-phenyl-5-(4-biphenylyl)-1,2,4-triazole(abbreviated to TAZ),3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole(abbreviated to p-EtTAZ), bathophenanthroline (abbreviated to BPhen),bathocuproin (abbreviated to BCP), or the like may be used. Thesubstances described here are a substance mainly having the electronmobility of 10⁻⁶ cm²/Vs or more. However, the present invention is notlimited to this, and another substance may be used as long as it has ahigher electron transporting property than a hole transporting property.It is to be noted that the electron transporting layer 105 may be formedof a single layer, a mixed layer, a stacked layer of two or more layersof these materials.

As the electron injecting layer 106, a compound of an alkali metal or analkaline earth metal, such as lithium fluoride (LiF), cesium fluoride(CsF), or calcium fluoride (CaF₂) can be used. In addition, a layer madefrom a substance having an electron transporting property may be used,in which an alkali metal, an alkaline earth metal, an alkali metalcompound, or an alkaline earth metal compound is contained. For example,Alq₃ containing lithium oxide (LiO_(x)), magnesium nitride (MgO_(x)),magnesium (Mg), or lithium (Li) can be used. By providing the electroninjecting layer 106 to be in contact with the second electrode 107 asthe present invention, an electron injecting barrier can be reduced. Asa result, a driving voltage of the light emitting element 100 can bereduced.

As the second electrode 107 (cathode), a metal, an alloy, an electricconductive compound, a mixture thereof, each of which has a low workfunction (specifically, work function of 3.8 eV or lower), or the like,can be used. As a specific example, an element belonging to Group 1 orGroup 2 in the periodic table, that is, an alkali metal such as lithium(Li) or cesium (Cs), an alkaline earth metal such as magnesium (Mg),calcium (Ca), or strontium (Sr), an alloy containing any of these (suchas MgAg or AlLi), a rare earth metal such as europium (Eu) or ytterbium(Yb), an alloy containing any of these, or the like may be used. Byproviding the electron injecting layer 106 to be in contact with thesecond electrode 107 between the second electrode 107 and the lightemitting layer 104, various conductive materials such as Al, Ag, ITO, orITSO can be used as the second electrode 107 regardless of high and lowof the work function.

The hole injecting layer 102, the hole transporting layer 103, the lightemitting layer 104, the electron transporting layer 105, and theelectron injecting layer 106 may be formed by an evaporation method. Inaddition, an inkjet method, a spin coating method, or the like may beused. Further, each electrode and each layer may be formed by differentformation methods.

In the light emitting element 100 of the present invention having theabove structure, a current flows due to a potential difference that isgenerated between the first electrode 101 and the second electrode 107,and holes and electrons are recombined in the light emitting layer 104,whereby light is emitted.

Light emission of the light emitting element 100 of the presentinvention can be extracted from one or both of the first electrode 101side and the second electrode 107 side by selecting the material of thefirst electrode 101 and the second electrode 107. For example, the firstelectrode 101 has a light transmitting property, and the secondelectrode 107 has a light shielding property (a reflecting property),whereby light can be extracted from the first electrode 101 side.Alternatively, the first electrode 101 has a light shielding property (areflective property), and the second electrode 107 has a lighttransmitting property, whereby light can be extracted from the secondelectrode 107 side. Alternatively, the first electrode 101 and thesecond electrode 107 have a light transmitting property, whereby lightcan be extracted from both electrodes side.

The light emitting element of this embodiment mode is not limited to theabove structure as long as the light emitting element has a structure inwhich at least the light emitting layer 104 is provided between thefirst electrode 101 and the second electrode 107. Accordingly, thestructure of the light emitting element may be appropriately changeddepending on the purpose.

Although the first electrode 101 is set to be an anode in thisembodiment mode, the present invention is not limited thereto, and thefirst electrode 101 may be set to be a cathode. In a case where thefirst electrode is set to be a cathode, an electron injecting layer incontact with the cathode, an electron transporting layer, a lightemitting layer, a hole transporting layer, a hole injecting layer, andthe second layer 107 that is to be an anode may be sequentially stacked.Also, in this case, a structure of the light emitting element can beappropriately changed depending on the purpose as long as the lightemitting element has a structure in which the light emitting layer isprovided between the first electrode 101 and the second electrode 107.

In the light emitting element 100 of the present invention, a pyrazinederivative of the present invention, which has a bipolar property, isused as a host material. As a result, light emission from a lightemitting compound that is a guest material can be efficiently obtained.In particular, light emission in a case of using a phosphorescentcompound as the guest material can be efficiently obtained.

(Embodiment Mode 3)

In this embodiment, a light emitting element that has a differentstructure from the structure shown in Embodiment Mode 2 will beexplained. It is to be noted that the structure except for the lightemitting layer is the same as that of Embodiment Mode 2; therefore,explanation thereof is omitted.

In a light emitting element 200 of the present invention shown in FIG.2, a light emitting layer 204 is provided between a first electrode 101and a second electrode 107, which is similar to the light emittingelement shown in Embodiment Mode 1. It is to be noted that an elementstructure is not limited to that shown in FIG. 2. The element structuremay be appropriately selected from the known structure depending on thepurpose as long as the structure has at least a pair of electrodes (thefirst electrode 101 and the second electrode 107) and a light emittinglayer provided between the pair of the electrodes.

In the light emitting element 200 of this embodiment mode, a layercontaining only a pyrazine derivative of the present invention, which isrepresented by any of the above general formulas (g-1) to (g-14), isused as the light emitting layer 204. A pyrazine derivative of thepresent invention, in which blue to green light emission colors can beobtained, can be favorably used in the light emitting element as a lightemitting compound.

Further, a pyrazine derivative of the present invention may be used as aguest material and dispersed into a host material. As the host materialto which the pyrazine derivative of the present invention is dispersed,one having larger energy gap than that of the pyrazine derivative of thepresent invention may be used. Specifically,9,10-di(2-naphthyl)anthracene (abbreviated to DNA),2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviated to t-BuDNA), orthe like can be used.

As described above, the pyrazine derivative of the present invention hasa bipolar property and serves as the light emitting compound.Accordingly, the pyrazine derivative of the present invention can beused as a material of the light emitting layer 204 without containinganother light emitting compound.

Since the pyrazine derivative of the present invention has a bipolarproperty, a light emitting region is rarely located at an interface of astacked film. Accordingly, a light emitting element, which has change ofa light emission spectrum due to mutual action such as exciplex and afavorable characteristic of small decrease of light emitting efficiency,can be obtained.

(Embodiment Mode 4)

In this embodiment mode, one example of a display device of the presentinvention and a manufacturing method thereof will be explained withreference to FIGS. 3A and 3B and FIG. 4. In this embodiment mode, anexample of an active matrix display device in which a pixel portion 370and a driver circuit portion 380 are formed over a same substrate willbe explained.

First, a base insulating film 301 is formed over a substrate 300. Whenlight is extracted from the substrate 300 side as a display surface, aglass substrate or a quartz substrate each of which has a lighttransmitting property may be used as the substrate 300. In addition, alight-transmitting plastic substrate that has resistance to a processingtemperature may be used. When light is extracted from an oppositesurface to the substrate 300 side as a display surface, a siliconsubstrate, a metal substrate, or a stainless substrate over which aninsulating film is formed may be used in addition to the abovesubstrate. At least a substrate that can resist heat generated during aprocess may be used. In this embodiment mode, a glass substrate is usedfor the substrate 300. A reflective index of the glass substrate isapproximately 1.55.

The base insulating film 301 is formed using an insulating film such asa silicon oxide film, a silicon nitride film, or a silicon oxynitridefilm by a sputtering method, an LPCVD method, a plasma CVD method, orthe like to have a single layer or a multi-layer of two or more layers.Further, the base insulating film is not necessary to be formed unlessunevenness of the substrate and diffusion of an impurity from thesubstrate become a problem.

Next, a semiconductor layer is formed over the base insulating film 301.After an amorphous semiconductor film is formed by a sputtering method,an LPCVD method, a plasma CVD method, or the like, the semiconductorfilm is crystallized by a laser crystallization method, a thermalcrystallization method, a thermal crystallization method using acatalytic element such as nickel to obtain a crystalline semiconductorfilm. In a case where a thermal crystallization method using a catalyticelement such as nickel is used, the catalytic element is preferablyremoved by gettering after the crystallization. Thereafter, thecrystalline semiconductor film is formed into a desired shape by aphotolithography method.

Subsequently, a gate insulating film 302 covering the semiconductorlayer is formed. As for the gate insulating film 302, an insulating filmcontaining silicon is formed with the use of a plasma CVD method or asputtering method. Alternatively, the gate insulating film 302 may beformed by performing surface nitriding treatment using plasma by amicrowave after an insulating film containing silicon that has asingle-layer structure or a stacked-layer structure is formed.

Then, a gate electrode is formed over the gate insulating film 302. Thegate electrode may be formed using a conductive material of a refractorymetal such as tungsten (W), chromium (Cr), tantalum (Ta), tantalumnitride (TaN), or molybdenum (Mo), or a conductive material of an alloyor a compound containing the refractory metal as its main component, orthe like by a sputtering method, an evaporation method, or the like. Thegate electrode may have a single-layer structure or a multi-layer of twoor more layers of these conductive materials.

Then, an impurity is added to each semiconductor layer in transistors310, 330, and 340 that are formed in the pixel portion 370 and thedriver circuit portion 380, in order to form an impurity region havingn-type or p-type conductivity. The impurity that is added may beappropriately selected in accordance with each transistor.

Next, first interlayer insulating films 303 a, 303 b, and 303 c areformed. As the first interlayer insulating films 303 a, 303 b, and 303c, an inorganic insulating film such as a silicon oxide film, a siliconnitride film, or a silicon oxynitride film, an organic resin film, or afilm containing siloxane can be used, and these insulating films may beformed to have a single layer or a multi-layer of two or more layers. Itis to be noted that siloxane is a material having a skeleton structureof a bond of silicon (Si) and oxygen (O). As a substituent, an organicgroup containing at least hydrogen (for example, an alkyl group havinggreater than or equal to 1 and less than or equal to 4 carbon atoms oraromatic hydrocarbon) can be used. In addition, a fluoro group may beused as the substituent. Further, as the substituent, an organic groupcontaining at least hydrogen and a fluoro group may be used. When aninorganic insulating film is formed, a sputtering method, an LPCVDmethod, a plasma CVD method, or the like may be used. When an organicresin film or a film containing siloxane is formed, a coating method maybe used. Although the first interlayer insulating films 303 a, 303 b,and 303 c have a three stacked-layer structure here, the interlayerinsulating film may have a single layer or a multi-layer.

Subsequently, the first interlayer insulating films 303 a, 303 b, and303 c are selectively etched to form a contact hole that reaches thesemiconductor layer. Then, a source electrode and a drain electrode thatreach a semiconductor layer through the contact hole are formed. After ametal film is stacked by a sputtering method, the source electrode andthe drain electrode are formed by selective etching of the metal stackedfilm by a photolithography method.

Through the above steps, the transistor 310 connected to a lightemitting element, a capacitor 311, a capacitor 311, and the transistor330 and the transistor 340 that are arranged in the driver circuitportion are formed. In this embodiment mode, in order to reduce anoff-current, the transistor 310 connected to the light emitting elementhas a multi-gate structure (a structure that has a semiconductor layerincluding two or more channel formation regions connected in series andtwo or more gate electrodes applying an electric field to each channelformation region). It is to be noted that the present invention is notlimited to this, and a single-gate structure such as the transistor 330and the transistor 340 may be employed. Although the transistor 330 andthe transistor 340 that are arranged in the driver circuit portion havethe single-gate structure, the present invention is not limited to this,and a multi-gate structure may be employed.

Further, each of the transistor 310, the transistor 330, and thetransistor 340 has a structure having a low concentration impurityregion (LDD region) that is overlapped with the gate electrode throughthe gate insulating film 302. It is to be noted that the presentinvention is not limited to this, and a structure without an LDD regionmay be employed.

In the pixel portion 370, a transistor 320 serving as a switchingelement is provided as shown in FIG. 3B. The transistor 320 has astructure having a low concentration impurity region (LDD region) thatis not overlapped with the gate electrode through the gate insulatingfilm 302. It is to be noted that the present invention is not limited tothis, and a structure without an LDD region may be employed.

In the driver circuit portion 380, the transistor 330 is set to be ann-channel, the transistor 340 is set to be a p-channel, and thetransistor 330 and the transistor 340 are complementary connected,whereby a CMOS circuit can be formed. By employing such a structure,various types of a circuit can be achieved.

Next, a second interlayer insulating film 304 is formed over the firstinterlayer insulating films 303 a, 303 b, and 303 c. As the secondinterlayer insulating film 304, an inorganic insulating film such as asilicon oxide film, a silicon nitride film, or a silicon oxynitride filmcan be formed. Alternatively, an organic resin film such as acryl orpolyimide, or a film containing siloxane may be used. Then, theseinsulating films may be formed of a single layer or a multi-layer of twoor more layers. It is to be noted that siloxane is a material having askeleton structure of a bond of silicon (Si) and oxygen (O). As asubstituent, an organic group containing at least hydrogen (for example,an alkyl group having greater than or equal to 1 and less than or equalto 4 carbon atoms or aromatic hydrocarbon) can be used. In addition, afluoro group may be used as the substituent. Further, as thesubstituent, an organic group containing at least hydrogen and a fluorogroup may be used. When an inorganic insulating film is formed, asputtering method, an LPCVD method, a plasma CVD method, or the like maybe used. When an organic resin film or a film containing siloxane isformed, a coating method may be used. Although the second interlayerinsulating film 304 has a single layer here, it may have a multi-layer.When an organic resin film, a film containing siloxane, or the like isused as the second interlayer insulating film 304, the second interlayerinsulating film 304 preferably has a stacked-layer structure includingan inorganic insulating film of a silicon oxide film, a silicon nitridefilm, and the like.

Subsequently, a light emitting element 350 is formed. First, a firstelectrode 351 (an anode or a cathode of an organic light emittingelement) is formed. The first electrode 351 is electrically connected tothe first transistor 310 through the second interlayer insulating film304. It is to be noted that the first electrode 351 may be formed in thesimilar manner to Embodiment Mode 2 and Embodiment Mode 3, andexplanation thereof is omitted.

Then, a partition layer 305 covering an edge portion of the firstelectrode 351 is formed. As for the partition layer 305, an insulatingfilm such as acryl, siloxane, resist, silicon oxide, or polyimide isformed by a coating method, and the obtained insulating film may beformed into a desired shape by a photolithography method.

Then, a layer 352, and a second electrode 353 (a cathode or an anode ofthe light emitting element) are sequentially formed. It is to be notedthat the layer 352 includes a layer containing a pyrazine derivative ofthe present invention represented by any of the general formulas (g-1)to (g-14), which is explained in Embodiment Mode 2 or Embodiment Mode 3.The layer 352 includes at least a light emitting layer. In addition, ahole injecting layer, a hole transporting layer, an electrontransporting layer, an electron injecting layer, or the like may beincluded. The layer 352 and the second electrode 353 may be formed in asimilar manner to Embodiment Mode 2 and Embodiment Mode 3, andexplanation thereof is omitted.

Through the above steps, the light emitting element 350 including thefirst electrode 351, the layer 352, and the second electrode 353 isformed. The light emitting element 350 is separated from anotheradjacent light emitting element by the partition layer 305.

Next, a sealing substrate 360 is sealed with a sealant 306 to seal thelight emitting element 350. In other words, a periphery of a displayregion is surrounded by the sealant 306, and a display device is sealedwith a pair of the substrates 300 and 360. Although the sealant 306 isprovided over the driver circuit portion 380 in this embodiment, thesealant 306 may be provided to surround at least the periphery of thedisplay device. A space 307 surrounded by the sealant 306 may be filledwith filler or a dried inert gas.

Finally, an FPC 393 is attached to a terminal electrode 391 with ananisotropic conductive layer 392 to constitute a terminal portion 390.In the terminal electrode 391, an electrode is preferably provided in anuppermost layer, which is obtained by the same step as that of a wiringelectrically connecting the transistor 310 and the first electrode 351to each other.

FIG. 4 shows a top view of the pixel portion. A cross-section of aportion shown by a dashed line A-A′ in FIG. 4 corresponds to across-sectional view of the pixel portion 370 in FIG. 3A. Although thepartition layer 305 covering an edge portion of the first electrode 351of the light emitting element, the layer 352, the second electrode 353,the sealing substrate 360, and the like are not shown in FIG. 4, theyare actually provided. FIGS. 3A and 3B and FIG. 4 are views showing oneexample of a display device of the present invention, and a wiring orthe like is appropriately changed depending on a layout.

In a display device of the present invention, a light emission displaysurface of the display device may be one surface or both surfaces. Whenthe first electrode 351 and the second electrode 353 are formed of atransparent conductive film, light from the light emitting element 350is extracted to both surface sides through the substrate 300 and thesealing substrate 360. In this case, a transparent material ispreferably used for the sealing substrate 360 and the filler.

When the second electrode 353 is formed of a metal film, and the firstelectrode 351 is formed of a transparent conductive film, light from thelight emitting element 350 is extracted to one surface side through onlythe substrate 300. That is, a bottom emission structure is made. In thiscase, a transparent material is not necessary to be used for the sealingsubstrate 360 and the filler.

When the first electrode 351 is formed of a metal film, and the secondelectrode 353 is formed of a transparent conductive film, light from thelight emitting element 350 is extracted to one surface side through onlythe sealing substrate 360. That is, a top emission structure is made. Inthis case, a transparent material is not necessary to be used for thesubstrate 300.

For the first electrode 351 and the second electrode 353, a material isneeded to be selected in consideration of the work function. However,both the first electrode 351 and the second electrode 353 may be ananode or a cathode depending on a pixel structure. When polarity of thetransistor 310 is a p-channel, the first electrode 351 is an anode, andthe second electrode 353 is a cathode. Alternatively, when polarity ofthe transistor 310 is an n-channel, the first electrode 351 is acathode, and the second electrode 353 is an anode.

A connection relation of the transistors 310 and 320, the capacitor 311,and the like is shown in a circuit diagram of FIG. 5. A gate electrodeof the transistor 320 is connected to a gate line 504, and one of asource region and a drain region of the transistor 320 is connected to asource line 505. The other of a source region and a drain region of thetransistor 310 is connected to a current supply line 506.

When the light emitting element 350 is a diode type element, and thetransistor 310 connected to the light emitting element 350 in series asthis embodiment is a p-channel transistor, the first electrode 351 ofthe light emitting element 350 serves as an anode. On the other hand,when the transistor 310 is an n-channel transistor, the first electrode351 of the light emitting element 350 serves as a cathode.

In the pixel portion of the display device of the present invention, aplurality of light emitting elements driven by the circuit shown in FIG.5 is arranged in matrix. A circuit for driving the light emittingelement is not limited to the circuit shown in FIG. 5. For example, acircuit may have a structure in which an erasing transistor that is usedfor an erasing line and erasing operation for forcibly erasing an inputsignal is provided or the like.

By including a light emitting element containing a pyrazine derivativeof the present invention as in this embodiment mode, a display deviceemitting light efficiently can be obtained.

(Embodiment Mode 5)

In this embodiment mode, an example of a passive display device will beexplained with reference to FIGS. 6A and 6B. FIG. 6A and FIG. 6Brespectively show a perspective view and a top view of a passive displaydevice to which the present invention is applied. In particular, FIG. 6Ais a perspective view of a portion surrounded by a dot line 658 of FIG.6B. Corresponding portions in each of FIG. 6A and FIG. 6B are denoted bythe same reference numerals. In FIG. 6A, a plurality of first electrodes652 is arranged in parallel over a first substrate 651. Each edgeportion of the first electrodes 652 is covered with a partition layer653. In order to easily recognize a state where the first electrode overthe first substrate 651 and the partition layer 653 are arranged, apartition layer that covers the first electrode 652 provided on the mostfront side is not shown in FIG. 6A. However, an edge portion of thefirst electrode 652 provided on the most front side is actually coveredwith the partition layer. A plurality of second electrodes 655 isprovided in parallel above the first electrodes 652, so as to intersectwith the plurality of the first electrodes 652. A layer 654 is providedbetween the first electrode 652 and the second electrode 655. It is tobe noted that the layer 654 includes a layer containing a pyrazinederivative of the present invention, which is explained in EmbodimentMode 2 or Embodiment Mode 3. The layer 654 includes at least a lightemitting layer. In addition, a hole injecting layer, a hole transportinglayer, an electron transporting layer, an electron injecting layer, orthe like may be included. A second substrate 659 is provided over thesecond electrode 655.

As shown in FIG. 6B, the first electrode 652 is connected to a firstdriver circuit 656, and the second electrode 655 is connected to asecond driver circuit 660. A portion where the first electrode 652 andthe second electrode 655 are intersected with each other forms a lightemitting element of the present invention, which is formed byinterposing the light emitting layer between the electrodes. Then, thelight emitting element of the present invention, which is selected by asignal from the first driver circuit 656 and the second driver circuit660, emits light. Light emission is extracted to outside through thefirst electrode 652, the second electrode 655, or the first electrode652 and the second electrode 655. Light emission from the plurality ofthe light emitting elements is combined to reflect an image. In order toeasily recognize each arrangement of the first electrode 652 and thesecond electrode 655, the partition layer 653 and the second substrate659 are not shown in FIG. 6B. However, they are actually provided asshown in FIG. 6A.

Although materials for forming the first electrode 652 and the secondelectrode 655 are not particularly limited, a transparent conductivefilm is preferably used so that one of or both the electrodes cantransmit visible light. Materials for the first substrate 651 and thesecond substrate 659 are not particularly limited, and each substratemay be formed using a material having flexibility with a resin such asplastic, in addition to a glass substrate or the like. A material of thepartition layer 653 is not particularly limited, and either an inorganicinsulating film or an organic insulating film may be used.Alternatively, both the inorganic insulating film and the organicinsulating film may be used. In addition, the partition layer 653 may beformed using siloxane.

It is to be noted that the layers 654 may be independently provided foreach light emitting element exhibiting light emission with differentcolor. For example, by providing independently the layers 654 for eachlight emitting element emitting light with a red color, a green color,and a blue color, a display device capable of multi-color display can beobtained.

By including a light emitting layer containing a pyrazine derivative ofthe present invention as in this embodiment mode, a passive displaydevice emitting light efficiently can be obtained.

(Embodiment Mode 6)

In this embodiment mode, a module using a panel that includes thedisplay device of the present invention as shown in Embodiment Mode 4will be explained with reference to FIGS. 7A and 7B.

FIG. 7A shows a module of an information terminal. In a panel 700, apixel portion 701 in which light emitting elements are provided in eachpixel, a first scanning line driver circuit 702 a and a second scanningline driver circuit 702 b that select a pixel included in the pixelportion 701, and a signal line driver circuit 703 that supplies a videosignal to a selected pixel are provided. The pixel portion 701corresponds to the pixel portion or the like in FIGS. 3A and 3B and FIG.4 explained in Embodiment 4.

A printed wiring board 710 is connected to the panel 700 through an FPC(flexible printed circuit) 704. A controller 711, a CPU (centralprocessing unit) 712, a memory 713, a power supply circuit 714, an audioprocessing circuit 715, and a transmission-reception circuit 716 aremounted on the printed wiring board 710 in addition to an element suchas a resistor, a buffer, or a capacitor element.

Various control signals are input and output through an interface (I/F)portion 717 provided over the printed wiring board 710. In addition, anantenna port 718 for transmitting and receiving signals to/from anantenna is provided over the printed wiring board 710.

Although the printed wiring board 710 is connected to the panel 700through the FPC 704 in this embodiment mode, the present invention isnot limited thereto. With the use of a COG (Chip on Glass) method, thecontroller 711, the audio processing circuit 715, the memory 713, theCPU 712, or the power supply circuit 714 may be directly mounted on thepanel 700. Further, various elements such as the capacitor element andthe buffer are provided over the printed wiring board 710, therebypreventing a noise in a power supply voltage or a signal and a dulledrise of a signal.

FIG. 7B shows a block diagram of the module shown in FIG. 7A. Thismodule includes, as the CPU 712, a control signal generating circuit720, a decoder 721, a register 722, an arithmetic circuit 723, a RAM724, an interface 725 for the CPU, and the like. Various signals inputto the CPU 712 through the interface 725 are input to the arithmeticcircuit 723, the decoder 721, or the like after being once held in theregister 722. The arithmetic circuit 723 operates based on the inputsignal and specifies an address to send various instructions. Meanwhile,a signal input to the decoder 721 is decoded and input to the controlsignal generating circuit 720. The control signal generating circuit 720generates a signal including various instructions based on the inputsignal and sends it to the address specified by the arithmetic circuit723, which is specifically the memory 713, the transmission-receptioncircuit 716, the audio processing circuit 715, the controller 711, orthe like.

As the memory 713, a VRAM 731, a DRAM 732, a flash memory 733, or thelike are provided. The VRAM 731 stores image data displayed on the panel700, the DRAM 732 stores image data or audio data, and the flash memory733 stores various programs.

The power supply circuit 714 generates a power supply voltage that isapplied to the panel 700, the controller 711, the CPU 712, the audioprocessing circuit 715, the memory 713, and the transmission-receptioncircuit 716. A current source may be provided in the power supplycircuit 714 depending on the specification of the panel.

The memory 713, the transmission-reception circuit 716, the audioprocessing circuit 715, and the controller 711 operate in accordancewith respective received instructions. Hereinafter, the operation isbriefly explained.

A signal input from an input unit 734 is transmitted to the CPU 712mounted on the printed wiring board 710 through the interface (I/F)portion 717. The control signal generating circuit 720 converts theimage data stored in the VRAM 731 into a predetermined format inaccordance with the signal transmitted from the input unit 734 such as apointing device or a keyboard, and then transmits it to the controller711.

The controller 711 processes a signal including the image data that istransmitted from the CPU 712 in accordance with the specification of thepanel and supplies it to the panel 700. The controller 711 generates andsupplies a Hsync signal, a Vsync signal, a clock signal CLK, analternating-current voltage (AC Cont), and a switching signal L/R to thepanel 700 based on the power supply voltage input from the power supplycircuit 714 or various signals input from the CPU 712.

In the transmission-reception circuit 716, a signal that is transmittedand received as an electric wave by an antenna 743 is processed.Specifically, a high frequency circuit such as an isolator, a band pathfilter, a VCO (Voltage Controlled Oscillator), an LPF (Low Pass Filter),a coupler, or a balan is included. Among the signals transmitted andreceived by the transmission-reception circuit 716, signals includingaudio data are transmitted to the audio processing circuit 715 inaccordance with an instruction transmitted from the CPU 712.

The signal including the audio data transmitted in accordance with theinstruction by the CPU 712 is demodulated into an audio signal in theaudio processing circuit 715 and transmitted to a speaker 748. Further,the audio signal transmitted from a microphone 747 is modulated in theaudio processing circuit 715 and transmitted to thetransmission-reception circuit 716 in accordance with the instructionfrom the CPU 712.

The controller 711, the CPU 712, the power supply circuit 714, the audioprocessing circuit 715, and the memory 713 can be mounted as a packageof the printed wiring board 710. This embodiment mode can be applied toany circuit other than a high frequency circuit such as an isolator, aband path filter, a VCO (Voltage Controlled Oscillator), an LPF (LowPass Filter), a coupler, or a balan.

As described above, by including a light emitting element containing apyrazine derivative of the present invention as a light emitting elementfor forming a panel, a module emitting light efficiently can beobtained.

(Embodiment Mode 7)

In this embodiment mode, an example in which a module including adisplay device of the present invention as shown in Embodiment Mode 5and Embodiment Mode 6 is mounted on a portable small-sized telephone set(cellular phone) operating wirelessly will be explained with referenceto FIGS. 7A and 7B and FIG. 8.

A display panel 800 is detachably incorporated in a housing 801 so as tobe easily fixed to a printed wiring board 810. The housing 801 can beappropriately changed in shape and size in accordance with an electronicdevice into which the housing 801 is incorporated.

In FIG. 8, the housing 801 to which the display panel 800 (correspondingto the panel 700 in FIGS. 7A and 7B) is fixed is fitted to the printedwiring board 810 (corresponding to the printed wiring board 710 in FIGS.7A and 7B) and set up as a module. On the printed wiring board 810, acontroller, a CPU, a memory, a power supply circuit, and other elementssuch as a resistor, a buffer, and a capacitor element are mounted.Moreover, an audio processing circuit including a microphone 804 and aspeaker 805 and a signal processing circuit 803 such as atransmission-reception circuit are provided. The display panel 800 isconnected to the printed wiring board 810 through an FPC as explained inFIGS. 7A and 7B.

Such a module 820, an input unit 808, and a battery 807 are stored in achassis 806. A pixel portion of the display panel 800 is arranged sothat it can be seen through a window formed in the chassis 806.

The chassis 806 shown in FIG. 8 shows an exterior shape of a telephoneset as an example. However, the present invention is not limitedthereto, and has various modes in accordance with functions andapplications.

As described above, by including a light emitting element containing apyrazine derivative of the present invention as a light emitting elementfor forming a display panel, a module of a small-sized telephone set(cellular phone) of which a display portion emits light efficiently orthe like can be obtained.

(Embodiment Mode 8)

In this embodiment mode, various electronic devices will be explained.For example, electronic devices will be explained, such as a camera suchas a video camera and a digital camera, a goggle type display (a headmounted display), a navigation system, an audio reproducing device (suchas a car audio or an audio component), a personal computer, a gamemachine, a portable information terminal (such as a mobile computer, acellular phone, a portable game machine, or an electronic book), and animage reproducing device provided with a recording medium (specifically,a device that reproduces a recording medium such as a Digital VersatileDisc (DVD) and has a display capable of displaying the reproducedimage).

FIG. 9A shows a digital video camera, which includes a main body 1801, adisplay device 1802, an imaging portion, operating keys 1804, a shutter1805, and the like. It is to be noted that FIG. 9A is a view of thedisplay portion 1802 side, and the imaging portion is not shown. Thedisplay portion 1802 includes a light emitting element containing apyrazine derivative of the present invention, whereby a favorabledisplay can be performed.

FIG. 9B shows a laptop personal computer, which includes a main body1821, a chassis 1822, a display portion 1823, a keyboard 1824, anexternal connecting port 1825, a pointing mouse 1826, and the like. Thedisplay device 1823 includes a light emitting element containing apyrazine derivative of the present invention, whereby a favorabledisplay can be performed.

FIG. 9C shows a portable image reproducing device provided with arecording medium (specifically, a DVD reproducing device), whichincludes a main body 1841, a chassis 1842, a display portion A 1843, adisplay portion B 1844, a recording medium (DVD or the like) readingportion 1845, operating keys 1846, a speaker portion 1847, and the like.The display portion A 1843 mainly displays image information, and thedisplay portion B 1844 mainly displays character information. It is tobe noted that the image reproducing device provided with a recordingmedium includes a home game machine and the like. The display portion A1843 and the display portion B 1844 includes a light emitting elementcontaining a pyrazine derivative of the present invention, wherebyfavorable display can be performed.

FIG. 9D shows a display device, which includes a chassis 1861, asupporting base 1862, a display portion 1863, a speaker 1864, a videoinput terminal 1865, and the like. It is to be noted that the displaydevice includes all information display devices such as those for acomputer, a television reception, an advertisement display, and thelike. The display portion 1863 includes a light emitting elementcontaining a pyrazine derivative of the present invention, wherebyfavorable display can be performed.

As described above, by including a light emitting element containing apyrazine derivative of the present invention in a display portion or thelike of various electronic devices, favorable display can be obtained.

Embodiment 1 Synthesis Example 1

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-9), that is, 2,3-bis{4-[N,N-di(biphenyl-4-yl)amino]phenyl}pyrazine(hereinafter, referred to as BBAPPr) will be explained.

[Step 1: Synthesis Method of 2,3-bis(4-bromophenyl)pyrazine(Hereinafter, Refereed to as PPr)]

(1) Synthesis of 2,3-bis(4-bromophenyl)-5,6-dihydropyrazine

10 g (27 mmol) of 4,4′-dibromobenzyl was put into a 300 mL three neckflask, and 200 mL of chloroform was added thereto to be dissolved. Then,3.0 mL (45 mmol) of etylendiamine was added thereto, and this mixturewas heated and stirred for 5 hours at 80° C. to be reacted. After thereaction, the reaction solution was washed with water, and a solvent wasremoved to obtain 10 g of a light yellow solid of2,3-bis(4-bromophenyl)-5,6-dihydropyrazine in the yield of 94%(Synthesis Scheme (e-1)).

(2) Synthesis of PPr

10 g (27 mmol) of 2,3-bis(4-bromophenyl)-5,6-dihydropyrazine was putinto a 500 mL three neck flask, and 100 mL of ethanol was added to bedissolved. Then, 8.8 g (54 mmol) of iron(III) chloride was addedthereto, and this mixture was heated and stirred for 30 minutes at 60°C. to be reacted. After the reaction, 300 mL of water was added to thereaction mixture, a precipitated solid was dissolved in toluene. Afterthis mixture was washed with saturated saline, the solid that wasobtained by concentrating the solvent was purified by silica columnchromatography. The purification by the silica column chromatography(hereinafter, also referred to as column purification) was performed asfollows: first, toluene was used as a developing solvent; and a mixedsolvent of toluene:ethyl acetate=1:1 was used as a developing solvent.After the column purification, the solvent of the obtained solution wasconcentrated to obtain 6.3 g of an orange solid of PPr in the yield of60% (Synthesis Scheme (e-2)).

[Step 2: Synthesis Method of di(biphenyl-4-yl)amine (Hereinafter,Referred to as BBA)](1) Synthesis of 4,4′-dibromodiphenylamine

50 g (169 mmol) of diphenylamine and 1000 mL of ethyl acetate were putinto a 2000 mL three neck flask, and 108 g (605 mmol) ofN-bromosuccinimide was added. This mixture was stirred for approximately12 hours at the room temperature to be reacted. After the reaction, thereaction solution was washed with water. An aqueous layer was extractedfrom the solution by ethyl acetate to be separated from an organiclayer, and the organic layer was dried with magnesium sulfate andfiltered. After the filtration, the filtrate was concentrated, and theobtained solid was washed with hexane, whereby 73 g of a white solid of4,4′-dibromophenylamine was obtained in the yield of 76% (SynthesisScheme (e-3)).

(2) Synthesis of BBA

30 g (92 mmol) of 4,4′-dibromodiphenylamine, 25 g of (204 mmol) ofphenylboronic acid, 0.46 g (2.0 mmol) of palladium acetate, and 1.4 g(4.5 mmol) of tris(o-tolyl)phosphine were put into a 500 mL three neckflask, and nitrogen was substituted for the content of the flask. Then,300 mL of ethylene glycol dimethylether and 300 mL (2.0 mol/L) ofpotassium carbonate solution were added thereto, and this mixture wasstirred for 5 hours at 80° C. to be reacted. After the reaction, aprecipitated object was filtered, and the filtered object wasre-crystallized with chloroform and hexane, whereby 23 g of a whitesolid of BBA was obtained in the yield of 78% (Synthesis Scheme (e-4)).

[Step 3: Synthesis Method of BBAPPr]

1.5 g of (3.9 mmol) of PPr, 2.5 g (7.7 mmol) of BBA, and 1.5 g (15.4mmol) of sodium-tert-butoxide were put into a 200 mL three neck flask,and nitrogen was substituted for the content of the flask. Then, 20 mLof toluene, 1.0 mL of a hexane solution (10 wt %) oftri-tert-butylphosphine, and 0.1 g (0.2 mmol) ofbis(dibenzylideneacetone)palladium(0) were added thereto, and thismixture was heated and stirred for 3 hours at 80° C. to be reacted.After the reaction, the reaction mixture was filtered through florisil,celite, and alumina. The filtrate was washed with water and dried withmagnesium sulfate, and then filtration was performed. A solid that wasobtained by concentrating the filtrate was dissolved in toluene to bepurified by silica column chromatography. For the column purification,first, toluene was used as a developing solvent, and then a mixedsolvent of toluene:ethyl acetate=9:1 was used as a developing solvent.After the column purification, the obtained solution was re-crystallizedwith chloroform and hexane, whereby 0.51 g of a yellow solid wasobtained in the yield of 15%.

The obtained yellow solid was sublimated and purified by a trainsublimation method. The sublimation and purification were performed for12 hours at 280° C. under the condition of 7 Pa of reduced pressure and3 mL/min of flow of argon. When the charged amount of the obtainedyellow solid was 0.51 g, 0.28 g of a yellow solid of BBAPPr that is anobject was obtained in the yield of 54% (Synthesis Scheme (e-5)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of BBAPPr is shown below. As a reference substance,tetramethylsilane (abbreviated to TMS) was used.

¹H-NMR (300 MHz, CDCl₃); δ=7.12-7.58 (m, 44H), δ=8.54 (s, 2H)

FIGS. 10A and 10B each show a ¹H-NMR chart of BBAPPr. FIG. 10B is anenlarged chart of a range of 6.5 to 9.0 ppm of the chart of FIG. 10A.

FIG. 11 shows an absorption spectrum and an emission spectrum in a statewhere BBAPPr is dissolved in a toluene solution. The ultraviolet-visiblespectrophotometer (V-550, manufactured by JASCO Corporation) was usedfor the measurement. In FIG. 11, the horizontal axis represents awavelength (nm) and the vertical axis represents intensity (arbitraryunit). Further, in FIG. 11, a line (a) indicates the absorption spectrumwhereas a line (b) indicates the emission spectrum (347 nm of an excitedwavelength).

In addition, an oxidation-reduction reaction characteristic of BBAPPrwas measured by cyclic voltammetry (CV) measurement. FIGS. 12A and 12Beach show a result thereof. Further, an electrochemical analyzer (ALSmodel 600A, manufactured by BAS Inc.) was used for the measurement.

As for a solution used in the CV measurement, dehydrateddimethylformamide (abbreviated to DMF) was used as a solvent.Tetra-n-butylammonium perchlorate (n-Bu₄NClO₄), which was a supportingelectrolyte, was dissolved in the solvent to have the concentration of100 mmol/L. Moreover, BBAPPr that is a measuring object was dissolved tohave the concentration of 1 mmol/L. Further, a platinum electrode (a PTEplatinum electrode, manufactured by BAS Inc.) was used as a workelectrode. A platinum electrode (a VC-3 Pt counter electrode (5 cm),manufactured by BAS Inc.) was used as an auxiliary electrode. An Ag/Ag⁺electrode (an RE5 nonaqueous solvent reference electrode, manufacturedby BAS Inc.) was used as a reference electrode.

The oxidation reaction characteristic was measured as follows: potentialof the work electrode with respect to the reference electrode wasscanned from at 0.10 to 1.00 V; and potential of the work electrode wasscanned from at 1.00 to 0.10 V. It is to be noted that the scanningspeed of the CV measurement was set to be at 0.1 V/s.

The reduction reaction characteristic was measured as follows: potentialof the work electrode with respect to the reference electrode wasscanned from at −0.84 to −2.70 V; and potential of the work electrodewas scanned from at −2.70 to −0.84 V. It is to be noted that thescanning speed of the CV measurement was set to be at 0.1 V/s.

A CV curved line for measuring the oxidation reaction characteristic ofBBAPPr is shown in FIG. 12A. Moreover, a CV curved line for measuringthe reduction reaction characteristic of BBAPPr is shown in FIG. 12B. Inboth FIGS. 12A and 12B, the horizontal axis indicates the potential ofthe work electrode with respect to the reference electrode, whereas thevertical axis indicates the current value flowing between the workelectrode and the auxiliary electrode. As shown in FIGS. 12A and 12B,both a peak showing oxidization and a peak showing reduction in BBAPPrwere definitely observed. In other words, it was found that BBAPPr is asubstance in which holes and electrons easily enter. From this, it wasfound that BBAPPr is a substance having a bipolar property.

Embodiment 2 Synthesis Example 2

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-16), that is,2,3-bis{4-[N-(biphenyl-4-yl)-N-phenylamino]phenyl}pyrazine (hereinafter,referred to as BPhAPPr), will be explained.

[Step 1: Synthesis Method of 4-phenyldiphenylamine (Hereinafter,Referred to as BPhA)]

40 g (172 mmol) of 4-bromobiphenyl, 19 g (206 mmol) of aniline, 0.99 g(1.7 mmol) of bis(dibenzylideneacetone)palladium(0), 41 g (429 mmol)sodium-tert-butoxide were put into a 500 mL three neck flask, andnitrogen was substituted for the content of the flask. Then, 300 mL oftoluene and 5.9 g (2.9 mmol) of a hexane solution (10 wt %) oftri-tert-butylphosphine were added thereto, and this mixture was stirredfor 2 hours at 80° C. to be reacted. After the reaction, the reactionmixture was washed with water. Then, an aqueous layer was extracted fromthe mixture by toluene to be separated from an organic layer, and theorganic layer was dried with magnesium sulfate and filtered. Then, asolid that was obtained by concentrating the filtrate was purified bysilica column chromatography, whereby 33 g of a white solid of BPhA thatis an object was obtained in the yield 80% (Synthesis Scheme (f-1)). Thecolumn purification was performed using toluene as a developingsolution.

[Step 2: Synthesis Method of BPhAPPr]

0.74 g (1.9 mmol) of PPr, 0.93 g (3.9 mmol) of BPhA, and 0.8 g ofsodium-tert-butoxide were put into a 200 mL three neck flask, andnitrogen was substituted for the content of the flask. Then, 70 mL oftoluene, 1.5 mL of a hexane solution (10 wt %) oftri-tert-butylphosphine, and 0.2 g (0.4 mmol) ofbis(dibenzylideneacetone)palladium(0) were added thereto, and thismixture was stirred for 3 hours at 80° C. to be reacted. After thereaction, the reaction mixture was filtered through florisil, celite,and alumina. The filtrate was washed with water and dried with magnesiumsulfate, and then filtration was performed. A solid that was obtained byconcentrating the filtrate was re-crystallized with dichloromethane andhexane, whereby 1.0 g of a yellow solid was obtained in the yield of70%.

The obtained yellow solid was sublimated and purified by a trainsublimation method. The sublimation and purification were performed for12 hours at 300° C. under the condition of 7 Pa of reduced pressure and3 mL/min of flow of argon. When the charged amount of the obtainedyellow solid was 1.0 g, 0.90 g of a yellow solid of BPhAPPr that is anobject was obtained in the yield of 90% (Synthesis Scheme (f-2)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of BPhAPPr is shown below. As a reference substance,tetramethylsilane (abbreviated to TMS) was used.

¹H-NMR (300 MHz, CDCl₃); δ=7.06-7.44 (m, 28H), δ=7.49 (d,J=9.0, 4H),δ=7.56 (d,J=7.2, 4H), δ=8.52 (s, 2H)

FIGS. 13A and 13B each show a ¹H-NMR chart of BPhAPPr. FIG. 13B is anenlarged chart of a range of 6.5 to 9.0 ppm of the chart of FIG. 13A.

FIG. 14 shows an absorption spectrum and an emission spectrum in a statewhere BPhAPPr is dissolved in a toluene solution. Theultraviolet-visible spectrophotometer (V-550, manufactured by JASCOCorporation) was used for the measurement. In FIG. 14, the horizontalaxis represents a wavelength (nm) and the vertical axis representsintensity (arbitrary unit). Further, in FIG. 14, a line (a) indicatesthe absorption spectrum whereas a line (b) indicates the emissionspectrum (352 nm of an excited wavelength).

FIG. 15 shows an absorption spectrum and an emission spectrum in asingle film state of BPhAPPr. The ultraviolet-visible spectrophotometer(V-550, manufactured by JASCO Corporation) was used for the measurement.In FIG. 15, the horizontal axis represents a wavelength (nm) and thevertical axis represents intensity (arbitrary unit). Further, in FIG.15, a line (a) indicates the absorption spectrum whereas a line (b)indicates the emission spectrum (336 nm of an excited wavelength).

Embodiment 3 Synthesis Example 3

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-13), that is, 2,3-bis[4-(N,N-diphenylamino)phenyl]pyrazine(hereinafter, referred to as DPhAPPr), will be explained.

[Step 1: Synthesis Method of DPhAPPr]

3.0 g (7.7 mmol) of PPr, 2.6 g (15.4 mmol) of diphenylamine(manufactured by Tokyo Chemical Industry Co., Ltd) (hereinafter,referred to as DPhA), and 3.0 g (30.8 mmol) of sodium-tert-butoxide wereput into a 200 mL three neck flask, and nitrogen was substituted for thecontent of the flask. Then, 40 mL of toluene, 0.3 mL of a hexanesolution (10 wt %) of tri-tert-butylphosphine, and 0.3 g (0.6 mmol) ofbis(dibenzylideneacetone)palladium(0) were added thereto, and thismixture was stirred for 5 hours at 80° C. to be reacted. After thereaction, the reaction mixture was filtered through florisil, celite,and alumina. The filtrate was washed with water and dried with magnesiumsulfate, and then filtration was performed. A solid that is obtained byconcentrating the filtrate was dissolved in toluene to be purified bysilica column chromatography. For the column purification, first,toluene was used as a developing solution, and then a mixed solvent oftoluene:ethyl acetate=9:1 was used as a developing solvent. After thecolumn purification, the obtained solution was re-crystallized withchloroform and hexane, whereby 3.5 g of a yellow solid was obtained inthe yield of 80%.

The obtained yellow solid was sublimated and purified by a trainsublimation method. The sublimation and purification were performed for12 hours at 240° C. under the condition of 7 Pa of reduced pressure and3 mL/min of flow of argon. When the charged amount of the yellow solidwas 3.5 g, 3.0 g of a yellow solid of DPhAPPr that is an object wasobtained in the yield of 86% (Synthesis Scheme (h-1)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of DPhAPPr is shown below. As a reference substance,tetramethylsilane (abbreviated to TMS) was used.

¹H-NMR (300 MHz, CDCl₃); δ=6.98-7.14 (m, 16H), δ=7.23-7.30 (m, 8H),δ=7.37 (d,J=9.0, 4H), δ=8.50 (s, 2H)

FIGS. 16A and 16B each show a ¹H-NMR chart of DPhAPPr. FIG. 16B is anenlarged chart of a range of 6.5 to 9.0 ppm of the chart of FIG. 16A.

FIG. 17 shows an absorption spectrum and an emission spectrum in a statewhere DPhAPPr is dissolved in a toluene solution. Theultraviolet-visible spectrophotometer (V-550, manufactured by JASCOCorporation) was used for the measurement. In FIG. 17, the horizontalaxis represents a wavelength (nm) and the vertical axis representsintensity (arbitrary unit). Further, in FIG. 17, a line (a) indicatesthe absorption spectrum whereas a line (b) indicates the emissionspectrum (364 nm of an excited wavelength).

FIG. 18 shows an absorption spectrum and an emission spectrum in asingle film state of DPhAPPr. In FIG. 18, the horizontal axis representsa wavelength (nm) and the vertical axis represents intensity (arbitraryunit). Further, in FIG. 18, a line (a) indicates the absorption spectrumwhereas a line (b) indicates the emission spectrum (368 nm of an excitedwavelength).

Embodiment 4 Synthesis Example 4

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-53), that is,2,3-bis{4-[N-(4-diphenylaminophenyl)-N-phenylamino]phenyl}pyrazine(hereinafter, referred to as DPAPPr), will be explained.

[Step 1: Synthesis Method of N,N,N′-triphenyl-1,4-phenylenediamine(hereinafter, referred to as DPA)]

(1) Synthesis of 4-bromotriphenylamine

25 g (100 mmol) of triphenylamine, 18 g (100 mmol) ofN-bromosuccinimide, and 400 mL of ethyl acetate were put into a 1000 mLErlenmeyer flask, and were stirred for approximately 12 hours at theroom temperature in the air to be reacted. After the reaction wascompleted, the reaction solution was washed twice with a saturatedsodium carbonate solution to separate an aqueous layer and an organiclayer. Then, the aqueous layer was extracted twice with ethyl acetate,and the extract was combined with the organic layer, and washed with asaturated saline solution. The solution was dried with magnesiumsulfate, and then filtration was performed. The filtrate wasconcentrated, and an obtained solid of 4-bromotriphenylamine wasre-crystallized with ethyl acetate and hexane, whereby 22 g of a whitepowder solid was obtained in the yield of 66% (Synthesis Scheme (i-1)).

(2) Synthesis of DPA

0.56 g (6 mmol) of 4-bromotriphenylamine, 0.35 g (0.6 mmol) ofbis(dibenzylideneacetone)palladium(0), and 0.58 g (6 mmol) ofsodium-tert-butoxide were put into a 100 mL three neck flask, and 5 mLof toluene was added thereto. After nitrogen was substituted for thecontent of the flask, 0.56 g (6 mmol) of aniline and 0.37 mL (1.8 mmol)of a hexane solution (10 wt %) of tri-tert-butylphosphine were added.This mixture was stirred for 5 hours at 80° C. to be reacted. After thereaction, the reaction was completed by adding a saturated salinesolution to the reaction mixture, and an aqueous layer was extracted byapproximately 100 mL of ethyl acetate to be separated from an organiclayer. The organic layer was dried with magnesium sulfate and filtered.A solid that was obtained by concentrating the filtrate was purified bysilica column chromatography, whereby 0.24 g of a light yellow powdersolid of DPA that is an object was obtained in the yield of 42%(Synthesis Scheme (i-2)). For the column purification, a mixed solventof ethyl acetate:hexane=1:20 was used as a developing solvent.

[Step 2: Synthesis Method of DPAPPr]

0.52 g (1.3 mmol) of PPr, 0.90 g (2.7 mmol) of DPA, and 0.8 g (8.3 mmol)of sodium-tert-butoxide were put into a 100 mL three neck flask, andnitrogen was substituted for the content of the flask. Then, 15 mL oftoluene and 0.1 mL of a hexane solution (10 wt %) oftri-tert-butylphosphine were added, and nitrogen was substituted for thecontent of the flask again. Moreover, 0.1 g (0.2 mmol) ofbis(dibenzylideneacetone)palladium(0) was added thereto, and thismixture was stirred for 5, hours at 120° C. to be reacted. After thereaction, the reaction mixture was filtered through celite. The filtratewas washed with water and dried with magnesium sulfate, and thenfiltration was performed. A solid that is obtained by concentrating thefiltrate was dissolved in toluene to be purified by silica columnchromatography. For the column purification, first, toluene was used asa developing solvent, and then a mixed solvent of toluene:ethylacetate=9:1 was used as a developing solvent. After the columnpurification, the obtained solution was re-crystallized with chloroformand hexane, whereby 0.27 g of a yellow solid of DPAPPr was obtained inthe yield of 80% (Synthesis Scheme (i-3)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of DPAPPr is shown below. As a reference substance,tetramethylsilane (abbreviated to TMS) was used.

¹H-NMR (300 MHz, CDCl₃); δ=6.99-7.26 (m, 42H), δ=7.37 (d, J=8.4, 4H),δ=8.49 (s, 2H)

FIGS. 19A and 19B each show a ¹H-NMR chart of DPAPPr. FIG. 19B is anenlarged chart of a range of 6.5 to 9.0 ppm of the chart of FIG. 19A.

FIG. 20 shows an absorption spectrum and an emission spectrum in a statewhere DPAPPr is dissolved in a toluene solution. The ultraviolet-visiblespectrophotometer (V-550, manufactured by JASCO Corporation) was usedfor the measurement. In FIG. 20, the horizontal axis represents awavelength (nm) and the vertical axis represents intensity (arbitraryunit). Further, in FIG. 20, a line (a) indicates the absorption spectrumwhereas a line (b) indicates the emission spectrum (358 nm of an excitedwavelength).

Embodiment 5 Synthesis Example 5

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-77), that is,2,3-bis{4-[N-phenyl-N-(9-phenylcarbazole-3-yl)amino]phenyl}pyrazine(hereinafter, referred to as PCAPPr), will be explained.

[Step 1: Synthesis Method of N-phenyl-(9-phenylcarbazole-3-yl)amine(Hereinafter, Referred to as PCA)]

(1) Synthesis of 3-bromo-9-phenylcarbazole

24.3 g (100 mmol) of N-phenylcarbazole was dissolved in 600 mL ofglacial acetic acid, 17.8 g (100 mmol) of N-bromosuccinimide was slowlyadded, and the mixture was stirred for approximately 12 hours at theroom temperature. This glacial acetic acid solution dropped to 1000 mLof iced water while being stirred. After the drop, a precipitated whitesolid was washed 3 times with water. This solid was dissolved in 150 mLof diethyl ether, and washed with a saturated sodium hydrogen carbonatesolution and water to separate an aqueous layer and an organic layer.This organic layer was dried with magnesium sulfate and filtered. Thefiltrate was concentrated to obtain a solid. Then, about 50 mL ofmethanol was added to the solid and the solid was uniformly dissolved byirradiation with ultrasonic waves. By leaving this solution at rest, awhite solid was extracted. This white solid was filtered and dried,whereby 28.4 g of a white powdered solid of 3-bromo-9-phenylcarbazolewas obtained in the yield of 88% (Synthesis Scheme (j-1)).

(Synthesis of PCA)

Under nitrogen, 110 mL of dehydrated xylene and 7.0 g (75 mmol) ofaniline were added to a mixture containing 19 g (60 mmol) of3-bromo-9-phenylcarbazole, 340 mg (0.6 mmol) ofbis(dibenzylideneacetone)palladium(0) (abbreviated to Pd(dba)₂), 1.6 g(3.0 mmol) of 1,1-bis(diphenylphosphino)ferrocene (abbreviated to DPPF),and 13 g (180 mmol) of sodium-tert-butoxide (abbreviated to t-BuONa).This mixture was then heated and stirred for 7.5 hours at 90° C. under anitrogen atmosphere. After the reaction was completed, approximately 500mL of toluene warmed to 50° C. was added to this suspension. Then, thesolution was filtered through florisil, alumina, and celite. Hexane andethyl acetate were added to a solid that was obtained by concentratingthe filtrate, and irradiation with ultrasonic waves was performed. Anobtained suspension was filtered and dried, whereby 15 g of a lightyellow solid of PCA was obtained in the yield of 75% (Synthesis Scheme(j-2)).

[Step 2: Synthesis Method of PCAPPr]

1.0 g (2.6 mmol) of PPr, 1.9 g (10.4 mmol) of PCA, and 1.0 g (10.3 mmol)of sodium-tert-butoxide were put into a 100 mL three neck flask, andnitrogen was substituted for the content of the flask. Then, 15 mL oftoluene, 0.3 mL of a hexane solution (10 wt %) oftri-tert-butylphosphine, and 0.1 g (0.2 mmol) ofbis(dibenzylideneacetone)palladium(0) were added thereto, and thismixture was stirred for 4 hours at 80° C. to be reacted. After thereaction, the reaction mixture was filtered through florisil, celite,and alumina. The filtrate was washed with water and dried with magnesiumsulfate, and then filtration was performed. A solid that was obtained byconcentrating the filtrate was dissolved in toluene to be purified bysilica column chromatography. For the column purification, first,toluene was used as a developing solvent, and then a mixed solvent oftoluene:ethyl acetate=9:1 was used as a developing solvent. After thecolumn purification, the obtained solution was re-crystallized withchloroform and hexane, whereby 1.3 g of a yellow solid was obtained inthe yield of 57%.

The obtained yellow solid was sublimated and purified by a trainsublimation method. The sublimation and purification were performed for12 hours at 330° C. under the condition of 7 Pa of reduced pressure and3 mL/min of flow of argon. When the charged amount of the yellow solidwas 1.2 g, 0.32 g of a yellow solid of PCAPPr that is an object wasobtained in the yield of 26% (Synthesis Scheme (j-3)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of PCAPPr is shown below. As a reference substance,tetramethylsilane (abbreviated to TMS) was used.

¹H-NMR (CDCl₃, 300 MHz); δ=6.97-7.67 (m, 40H), δ=7.93-7.97 (m, 2H),δ=8.48 (s, 2H)

FIGS. 21A and 21B each show a ¹H-NMR chart of PCAPPr. FIG. 21B is anenlarged chart of a range of 6.5 to 9.0 ppm of the chart of FIG. 21A.

FIG. 22 shows an absorption spectrum and an emission spectrum in a statewhere PCAPPr is dissolved in a toluene solution. The ultraviolet-visiblespectrophotometer (V-550, manufactured by JASCO Corporation) was usedfor the measurement. In FIG. 22, the horizontal axis represents awavelength (nm) and the vertical axis represents intensity (arbitraryunit). Further, in FIG. 22, a line (a) indicates the absorption spectrumwhereas a line (b) indicates the emission spectrum (367 nm of an excitedwavelength).

FIG. 23 shows an absorption spectrum and an emission spectrum in asingle film state of PCAPPr. The ultraviolet-visible spectrophotometer(V-550, manufactured by JASCO Corporation) was used for the measurement.In FIG. 23, the horizontal axis represents a wavelength (nm) and thevertical axis represents intensity (arbitrary unit). Further, in FIG.23, a line (a) indicates the absorption spectrum whereas a line (b)indicates the emission spectrum (376 nm of an excited wavelength).

Embodiment 6 Synthesis Example 6

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-103), that is,2,3-bis(4-{N-[4-(carbazole-9-yl)phenyl]-N-phenylamino}phenyl)pyrazine(hereinafter, referred to as YGAPPr), will be explained.

[Step 1: Synthesis Method of 4-(carbazole-9-yl)diphenylamine(Hereinafter, Referred to as YGA)]

(1) Synthesis of 9-(4-bromophenyl)carbazole

56 g (240 mmol) of p-dibromobenzene, 31 g (180 mmol) of carbazole, 4.6 g(24 mmol) of copper iodide, 66 g (480 mmol) of potassium carbonate, and2.1 g (8 mmol) of 18-crown-6-ether were put into a 300 mL three-neckedflask, and nitrogen was substituted for the content of the flask. Then,8 mL of N—N′-dimetylpropyleneurea was added thereto, and this mixturewas stirred for 6 hours at 180° C. to be reacted. After the reaction,cooling of the reaction mixture to the room temperature was performed,and the precipitated object was removed by suction filtration. Thefiltrate was washed with dilute hydrochloric acid, a saturated sodiumhydrogen carbonate solution, and a saturated saline solution, in thisorder, and then dried with magnesium sulfate. After drying, filtrationwas performed, and an oily substance that was obtained by concentratingthe filtrate was purified by silica column chromatography. For thecolumn purification, a mixed solvent of hexane:ethyl acetate=9:1 wasused as a developing solvent. After the column purification, an obtainedsolution was re-crystallized with chloroform and hexane, whereby 21 g ofa light brown solid of 9-(4-bromophenyl)carbazole was obtained in theyield of 35% (Synthesis Scheme (k-1)).

(2) Synthesis of YAG

5.4 g (17 mmol) of 9-(4-bromophenyl)carbazole, 1.8 mL (20 mmol) ofaniline, 0.1 g (0.2 mmol) of bis(dibenzylideneacetone)palladium(0), and3.9 g (40 mmol) of sodium-tert-butoxide were put into a 200 mL threeneck flask. After nitrogen was substituted for the content of the flask,0.1 mL of a hexane solution (10 wt %) of tri-tert-butylphosphine and 50mL of toluene were added. This mixture was stirred for 6 hours at 80° C.to be reacted. After the reaction, the reaction mixture was filteredthrough florisil, celite, and alumina. The filtrate was washed withwater and a saturated saline solution, dried with magnesium sulfate, andfiltration was naturally performed. An oily substance that was obtainedby concentrating the filtrate was purified by silica gel columnchromatography, whereby 4.1 g of a white solid of YGA was obtained inthe yield of 73% (Synthesis Scheme (k-2)). For the column purification,a mixed solvent of hexane:ethyl acetate=9:1 was used as a developingsolvent.

[Step 2: Synthesis Method of YGAPPr]

2.0 g (5.1 mmol) of PPr, 3.5 g (10.5 mmol) of YGA, and 1.9 g (20.1 mmol)of sodium-tert-butoxide were put into a 100 mL three neck flask, andnitrogen was substituted for the content of the flask. Then, 30 mL oftoluene and 0.2 mL of a hexane solution (10 wt %) oftri-tert-butylphosphine were added, and nitrogen was substituted for thecontent of the flask again. Moreover, 0.2 g (0.4 mmol) ofbis(dibenzylideneacetone)palladium(0) was added thereto, and thismixture was heated and stirred for 5 hours at 120° C. to be reacted.After the reaction, the reaction mixture was filtered through celite.The filtrate was washed with water and dried with magnesium sulfate, andthen filtration was performed. A solid that was obtained byconcentrating the filtrate was dissolved in toluene to be purified bysilica column chromatography. For the column purification, first,toluene was used as a developing solvent, and then a mixed solvent oftoluene:ethyl acetate=9:1 was used as a developing solvent. After thecolumn purification, an obtained solution was re-crystallized withchloroform and hexane, whereby 4.1 g of a yellow solid was obtained inthe yield of 89%.

The obtained yellow solid was sublimated and purified by a trainsublimation method. The sublimation and purification were performed for12 hours at 320° C. under the condition of 7 Pa of reduced pressure and3 mL/min of flow of argon. When the charged amount of the yellow solidwas 3.4 g, 0.65 g of a yellow solid of YGAPPr that is an object wasobtained in the yield of 19% (Synthesis Scheme (k-3)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of YGAPPr is shown below. As a reference substance,tetramethylsilane (abbreviated to TMS) was used.

¹H-NMR (300 MHz, CDCl₃): δ=7.11 (d, J=12.0, 4H), δ=7.16-7.44 (m, 26H),δ=7.48 (d, J=8.4, 4H), δ=8.13 (d, J=7.8, 4H), δ=8.55 (s, 2H)

FIGS. 24A and 24B each show a ¹H-NMR chart of YGAPPr. FIG. 24B is anenlarged chart of a range of 6.5 to 9.0 ppm of the chart of FIG. 24A.

FIG. 25 shows an absorption spectrum and an emission spectrum in a statewhere YGAPPr is dissolved in a toluene solution. The ultraviolet-visiblespectrophotometer (V-550, manufactured by JASCO Corporation) was usedfor the measurement. In FIG. 25, the horizontal axis represents awavelength (nm) and the vertical axis represents intensity (arbitraryunit). Further, in FIG. 25, a line (a) indicates the absorption spectrumwhereas a line (b) indicates the emission spectrum (355 nm of an excitedwavelength).

FIG. 26 shows an absorption spectrum and an emission spectrum in asingle film state of YGAPPr. The ultraviolet-visible spectrophotometer(V-550, manufactured by JASCO Corporation) was used for the measurement.In FIG. 26, the horizontal axis represents a wavelength (nm) and thevertical axis represents intensity (arbitrary unit). Further, in FIG.26, a line (a) indicates the absorption spectrum whereas a line (b)indicates the emission spectrum in the single film state (375 nm of anexcited wavelength).

Embodiment 7

In this embodiment, an example of a light emitting element will bespecifically described, in which DPhAPPr (the structural formula (s-13))that is one example of a pyrazine derivative of the present inventionsynthesized in Synthesis Example 3 of Embodiment 3 is used as a hostmaterial of a light emitting layer, and a phosphorescent compound isused as a guest material. An element structure is shown in FIG. 27.

First, a glass substrate 7000 over which indium tin oxide containingsilicon (ITSO) with a thickness of 100 nm is formed was prepared. Aperiphery of the ITSO was covered with an insulating film. At this time,the insulating film was formed so that a surface of the ITSO was exposedwith a size of 2×2 mm. It is to be noted that the ITSO is a firstelectrode 7001 serving as an anode of a light emitting element. As apretreatment for forming a light emitting element over the substrate7000 over which the first electrode 7001 was formed, a surface of thesubstrate 7000 was washed with a porous resin brush, baked for 1 hour at200° C., and subjected to UV ozone treatment for 370 seconds.

Next, the substrate 7000 was fixed to a holder provided in a vacuumevaporation device in such a way that a surface over which the firstelectrode 7001 was formed faces downward.

Subsequently, the pressure in the vacuum evaporation device was reducedto 10⁻⁴ Pa. NPB represented by the following structural formula (s-116)and molybdenum oxide (VI) were co-evaporated over the first electrode7001 so that the ratio thereof is to be NPB:molybdenum oxide (VI)=4:1 inthe mass ratio, thereby forming a hole injecting layer 7002. The holeinjecting layer 7002 was formed to have a thickness of 50 nm. It is tobe noted that the co-evaporation is an evaporation method in which aplurality of substances different from each other is simultaneouslyevaporated from evaporation sources different from each other.

Then, 10 nm of NPB was evaporated over the hole injecting hole layer7002, thereby forming a hole transporting layer 7003. In addition,DPhAPPr (the structural formula (s-13)) that is a pyrazine derivative ofthe present invention and a phosphorescent compound that is(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(hereinafter, referred to as Ir(Fdpq)₂(acac)) represented by thefollowing structural formula (s-117) were co-evaporated over the holetransporting layer 7003 so that the ratio thereof is set to beDPhAPPr:Ir(Fdpq)₂(acac)=1:0.05 in the mass ratio, thereby forming alight emitting layer 7004. The light emitting layer 7004 was formed tohave a thickness of 30 nm. Accordingly, Ir(Fdpq)₂(acac) is dispersed ina layer made from DPhAPPr (the structural formula (s-13)) that is apyrazine derivative of the present invention.

Then, 10 nm of BAlq represented by the following structural formula(s-118) was evaporated over the light emitting layer 7004 to have athickness of 10 nm, thereby forming an electron transporting layer 7005.In addition, Alq₃ represented by the following structural formula(s-119) and lithium (Li) were co-evaporated over the electrontransporting layer 7005 so that the ratio thereof is set to beAlq₃:Li=1:0.01 in the mass ratio, thereby forming an electron injectinglayer 7006. The electron injecting layer was formed to have a thicknessof 50 nm.

Finally, 200 nm of aluminum as a second electrode 7007 was formed overthe electron injecting layer 7006, thereby obtaining a light emittingelement 7010 of this embodiment. It is to be noted that the secondelectrode 7007 served as a cathode. Further, in the above evaporationprocess, a heat resistance method was used for the entire evaporation.

By placing the light emitting element 7010 of this embodiment in agloved box under a nitrogen atmosphere, sealing of the light emittingelement 7010 was performed so that the light emitting element 7010 wasnot exposed to the atmospheric air. Then, an operation characteristic ofthe light emitting element 7010 of this embodiment was measured. Themeasurement was performed at the room temperature (in the atmospherewhere the temperature was held at 25° C.).

FIG. 28 shows a current density-luminance characteristic of the lightemitting element 7010 of this embodiment, and FIG. 29 shows avoltage-luminance characteristic thereof. In the light emitting element7010 of this embodiment, by applying a voltage of 7.2 V, the currentflowed with the current density of 23.4 mA/cm², and light was emittedwith the luminance of 843 cd/m². The CIE chromaticity coordinate at thistime was (x=0.70, y=0.29), and light emission with deep red color wasexhibited. A peak wavelength of an emission spectrum was 640 nm, andlight emission from Ir(Fdpq)₂(acac) that is a guest material wasobtained.

FIG. 30 shows a luminance-current efficiency characteristic of the lightemitting element 7010. FIG. 31 shows a graph in which a vertical axis ofFIG. 30 is converted to external quantum efficiency. As shown in FIG. 30and FIG. 31, the maximum current efficiency was 8.63 cd/A, the externalquantum efficiency at this time was 17.0%, and extremely high lightemitting efficiency was shown.

According to the above, a light emitting element is manufactured byusing a pyrazine derivative of the present invention as a host materialof a light emitting layer and a phosphorescent compound as a guestmaterial, whereby it was found that a light emitting element havingextremely high light emitting efficiency can be obtained.

Embodiment 8

In this embodiment, a light emitting element having different structurefrom that shown in Embodiment 7 will be explained. It is to be notedthat the light emitting element except for an electron transportinglayer 8005 has the same structure as that of Embodiment 7; therefore,explanation thereof is omitted. An element structure is shown in FIG.32.

In this embodiment, Alq₃ was used for the electron transporting layer8005 replacing with BAlq used in Embodiment 7. The other structure issimilar to that of Embodiment 7.

FIG. 33 shows a current density-luminance characteristic of a lightemitting element 8010 of this embodiment, and FIG. 34 shows avoltage-luminance characteristic thereof. In the light emitting element8010 of this embodiment, by applying a voltage of 6.4 V, a currentflowed with the current density of 25.5 mA/cm², and light was emittedwith the luminance of 927 cd/m². The CIE chromaticity coordinate at thistime was (x=0.68, y=0.31), and light emission with deep red color wasexhibited. A peak wavelength of an emission spectrum was 640 nm, andlight emission from Ir(Fdpq)₂(acac) that is a guest material can beobtained.

FIG. 35 shows a luminance-current efficiency characteristic of the lightemitting element 8010 of this embodiment. FIG. 36 is a graph in which avertical axis of FIG. 35 is converted to external quantum efficiency. Asshown in FIG. 35 and FIG. 36, the maximum current efficiency was 6.16cd/A, the external quantum efficiency at this time was 11.7%, and highlight emitting efficiency was shown.

According to the above, a light emitting element is manufactured byusing a pyrazine derivative of the present invention as a host materialof the light emitting layer 7004 and a phosphorescent compound as aguest material, whereby it was found that a light emitting elementhaving extremely high light emitting efficiency can be obtained. In thisembodiment, Alq₃ is used for the electron transporting layer 8005provided in contact with the light emitting layer 7004. Alq₃ isgenerally known as a quench for quenching light emission of aphosphorescent compound. However, in this embodiment, the electrontransporting layer 8005 made from Alq₃ is in contact with the lightemitting layer 7004, and a light emitting element having high lightemitting efficiency can be achieved. As a reason of this, it isconsidered that a pyrazine derivative of the present invention has abipolar property for transporting electrons as well as holes.

Embodiment 9 Synthesis Example 7

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-14), that is,2,3-bis[4-(N,N-diphenylamino)phenyl]5,6-diphenylpyrazine (hereinafter,referred to as DPhAPPPr), will be explained.

[Step 1: Synthesis Method of 2,3-bis(4-bromophenyl)-5,6-diphenylpyrazine(Hereinafter, Referred to as PPPr)]

3.0 g (8.1 mmol) of 4,4′-dibromobenzyl and 1.8 g (8.1 mmol) ofmeso-diphenlyetylenediamine were put into a 300 mL three neck flask, 100mL of ethanol was added thereto, and this mixture was heated and stirredfor 5 hours at 80° C. to be reacted. After the reaction, the reactionsolution was concentrated, and 2.3 g of manganese dioxide and 100 mL ofchloroform were added thereto. Then, the solution was further heated andstirred for 1 hour at 80° C. to be reacted. After the reaction, thereaction solution was washed with water, and an aqueous layer and anorganic layer were separated. The organic layer was subjected to suctionfiltration through celite. A solid that was obtained by concentratingthe filtrate was washed with a mixed solvent of chloroform and hexane,whereby 1.6 g of a white powder solid of PPPr was obtained in the yieldof 37% (Synthesis Scheme (l-1)).

[Step 2: Synthesis Method of DPhAPPPr]

3.2 g (5.9 mmol) of PPPr, 2.0 g (12 mmol) of DPhA, and 1.5 g (16 mmol)of sodium-tert-butoxide were put into a 200 mL three neck flask. Afternitrogen was substituted for the content of the flask, 30 mL of toluene,0.1 mL of a hexane solution (10 wt %) of tri-tert-butylphosphine, and0.1 g (0.2 mmol) of bis(dibenzylideneacetone)palladium(0) were addedthereto. This mixture was heated and stirred for 8 hours at 120° C. tobe reacted. After the reaction, chloroform was added to the reactionmixture to dissolve the precipitated object, and the reaction mixturewas subjected to suction and filtration through florisil, celite, andalumina. The filtrate was washed with water, dried with magnesiumsulfate, and subjected to suction and filtration. Then, by concentratingthe filtrate, an obtained solid was washed with a mixed solvent oftoluene and methanol, and re-crystallization was performed withchloroform and methanol, whereby 1.8 g of a yellow powder solid wasobtained in the yield of 42%.

The obtained yellow solid was sublimated and purified by a trainsublimation method. The sublimation and purification were performed for15 hours at 294° C. under the condition of 7 Pa of reduced pressure and3 mL/min of flow of argon. When the charged amount of the obtainedyellow solid was 1.8 g, 1.3 g of a yellow solid of DPhAPPPr that is anobject was obtained in the yield of 72% (Synthesis Scheme (1-2)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of DPhAPPPr that was obtained is shown below. As a referencesubstance, TMS was used.

¹H-NMR (300 MHz, CDCl₃); δ=6.95-7.18 (m, 16H), δ=7.22-7.40 (m, 14H),δ=7.57 (d, J=8.3, 4H), δ=7.60-7.68 (m, 4H)

FIGS. 37A and 37B each show a ¹H-NMR chart of DPhAPPPr. FIG. 37B is anenlarged chart of a range of 6.5 to 8.0 ppm of the chart of FIG. 37A.

FIG. 38 shows an absorption spectrum and an emission spectrum in a statewhere DPhAPPPr is dissolved in a toluene solution. Theultraviolet-visible spectrophotometer (V-550, manufactured by JASCOCorporation) was used for the measurement. In FIG. 38, the horizontalaxis represents a wavelength (nm) and the vertical axis representsintensity (arbitrary unit). Further, in FIG. 38, a line (a) indicatesthe absorption spectrum whereas a line (b) indicates the emissionspectrum (371 nm of an excited wavelength).

Embodiment 10 Synthesis Example 8

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-52), that is,2,3-bis(4-{N-[4-(carbazole-9-yl)phenyl]-N-phenylamino}phenyl)-5,6-diphenylpyrazine(hereinafter, referred to as YGAPPPr), will be explained.

1.6 g (3.0 mmol) of PPPr, 2.0 g (6.0 mmol) of YGA, and 1.1 g (11 mmol)of sodium-tert-butoxide were put into a 100 mL three neck flask. Afternitrogen was substituted for the content of the flask, 30 mL of tolueneand 0.1 mL of a hexane solution (10 wt %) of tri-tert-butylphosphinewere added thereto. Then, nitrogen was substituted for the content ofthe flask again, and 0.1 g (0.2 mmol) ofbis(dibenzylideneacetone)palladium(0) were added. This mixture washeated and stirred for 5 hours at 80° C. to be reacted. After thereaction, toluene was added to the reaction mixture to dissolve theprecipitated object, and the reaction mixture was subjected to suctionand filtration through celite, florisil, and alumina. The filtrate waswashed with water, dried with magnesium sulfate, and subjected tosuction and filtration. A solid that was obtained by concentrating thefiltrate was dissolved in toluene to be purified by silica columnchromatography. For the column purification, first, a mixed solvent oftoluene:hexane=1:1 was used as a developing solvent, and then toluenewas used as a developing solvent. After the column purification, a solidthat was extracted by concentrating the obtained solution wasre-crystallized with chloroform and hexane, whereby 1.0 g of a yellowpowder solid was obtained in the yield of 16% (Synthesis Scheme (m-1)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of YGAPPPr that was obtained is shown below. As a referencesubstance, TMS was used.

¹H-NMR (300 MHz, CDCl₃); δ=7.00-7.10 (m, 2H), δ=7.16 (d, J=8.8, 4H),δ=7.21-7.47 (m, 34H), δ=7.62-7.77 (m, 8H), δ=8.13 (d, J=7.3, 4H)

FIGS. 39A and 39B each show a ¹H-NMR chart of YGAPPPr. FIG. 39B is anenlarged chart of a range of 6.5 to 8.5 ppm of the chart of FIG. 39A.

FIG. 40 shows an absorption spectrum and an emission spectrum in a statewhere YGAPPPr is dissolved in a toluene solution. Theultraviolet-visible spectrophotometer (V-550, manufactured by JASCOCorporation) was used for the measurement. In FIG. 40, the horizontalaxis represents a wavelength (nm) and the vertical axis representsintensity (arbitrary unit). Further, in FIG. 40, a line (a) indicatesthe absorption spectrum whereas a line (b) indicates the emissionspectrum (371 nm of an excited wavelength).

Embodiment 11

In this embodiment, an example of a light emitting element will bespecifically described, in which DPhAPPPr (the structural formula(s-14)) that is one example of a pyrazine derivative of the presentinvention synthesized in Synthesis Example 7 of Embodiment 9 is used asa host material of a light emitting layer, and a phosphorescent compoundis used as a guest material. FIG. 49 shows an element structure. It isto be noted that the light emitting element except for a light emittinglayer 9004 has the same structure as that of Embodiment 7; therefore,explanation thereof is omitted.

In this embodiment, the light emitting layer 9004 was formed byco-evaporating DPhAPPPr that is a pyrazine derivative (the structuralformula (s-14)) and a phosphorescent compound represented by the abovestructural formula (s-117), that is,(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(hereinafter, referred to as Ir(Fdpq)₂(acac)) so that a ratio thereofwas set to be 1:0.07 in a mass ratio. The light emitting layer 9004 wasformed to have a thickness of 30 nm. Accordingly, Ir(Fdpq)₂(acac) isdispersed in a layer made from DPhAPPPr (the structural formula (s-14))that is a pyrazine derivative of the present invention. Other structuresare the same as those of Embodiment 7.

FIG. 41 shows a current density-luminance characteristic of the lightemitting element 9010 of this embodiment, and FIG. 42 shows avoltage-luminance characteristic thereof. FIG. 43 shows aluminance-current efficiency characteristic thereof, and FIG. 44 showsan emission spectrum. In the light emitting element 7010 of thisembodiment, by applying a voltage of 8.2 V, a current flowed with thecurrent density of 34.1 mA/cm², and light was emitted with the luminanceof 1100 cd/m². The current efficiency at this time was 3.1 cd/A. Theemission spectrum has a peak in 647 nm, and light emission with a redcolor that is derived from Ir(Fdpq)₂(acac) of a guest material wasobtained. The CIE chromaticity coordinate at 1100 cd/m² was (x=0.71,y=0.29), and light emission with a deep red color having high colorpurity was exhibited.

According to the above, a light emitting element is manufactured byusing a pyrazine derivative of the present invention as a host materialof a light emitting layer and a phosphorescent compound as a guestmaterial, whereby it was found that a light emitting element havingextremely high light emitting efficiency can be obtained.

Embodiment 12

In this embodiment, an example of a light emitting element will bespecifically described, in which YGAPPPr (the structural formula (s-52))that is one example of a pyrazine derivative of the present inventionsynthesized by Synthesis Example 8 of Embodiment 10 is used as a hostmaterial of a light emitting layer, and a phosphorescent compound isused as a guest material. FIG. 50 shows an element structure. It is tobe noted that the light emitting layer except for a light emitting layer5004 has the same structure as that of Embodiment 7; therefore,explanation thereof is omitted.

In this embodiment, the light emitting layer 5004 was formed byco-evaporating YGAPPPr (the structural formula (s-52)) that is apyrazine derivative and a phosphorescent compound represented by theabove structural formula (s-117), that is,(acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III)(hereinafter, referred to as Ir(Fdpq)₂(acac)) so that a ratio thereofwas set to be 1:0.07 in a mass ratio. The light emitting layer 5004 wasformed to have a thickness of 30 nm. Accordingly, Ir(Fdpq)₂(acac) isdispersed in a layer made from YGAPPPr (the structural formula (s-52))that is a pyrazine derivative of the present invention. Other structuresare the same as those of Embodiment 7.

FIG. 45 shows a current density-luminance characteristic of a lightemitting element 7010 of this embodiment, and FIG. 46 shows avoltage-luminance characteristic thereof. FIG. 47 shows aluminance-current efficiency characteristic thereof, and FIG. 48 showsan emission spectrum. In the light emitting element 5010 of thisembodiment, by applying a voltage of 8.0 V, a current flowed with thecurrent density of 36.4 mA/cm², and light was emitted with the luminanceof 1100 cd/m². The current efficiency at this time was 3.1 cd/A. Theemission spectrum has a peak in 650 nm, and light emission with a redcolor that is derived from Ir(Fdpq)₂(acac) of a guest material wasobtained. The CIE chromaticity coordinate at 1100 cd/m² was (x=0.71,y=0.29), and light emission with a deep red color having extremely highcolor purity was exhibited.

According to the above, a light emitting element is manufactured byusing a pyrazine derivative of the present invention as a host materialof a light emitting layer and a phosphorescent compound as a guestmaterial, whereby it was found that a light emitting element havingextremely high light emitting efficiency can be obtained.

Embodiment 13 Synthesis Example 10

As one example of a pyrazine derivative of the present invention, asynthesis method of a compound represented by a structural formula(s-88), that is,2-(4-{N-[4-(carbazole-9-yl)phenyl]-N-phenylamino}phenyl)-3,5,6-triphenylpyrazine(hereinafter, referred to as YGA1PPPr), will be explained.

[Step 1: Synthesis Method of 2-(4-bromophenyl)-3,5,6-triphenylpyrazine(Hereinafter, Referred to as 1PPPr)]

(1) Synthesis of 1-(4-bromophenyl)-2-phenylacetylene

28.3 g (0.10 mol) of p-bromoiodebenzene, 10.2 g (0.10 ml) ofphenylacetylene, 0.70 g (1.0 mmol) ofbis(triphenylphosphine)palladium(II)dichloride, and 0.19 g (1.0 mmol) ofcopper iodide (I) were put into a 1000 mL three neck flask, and nitrogenwas substituted for the content of the flask. Then, 350 mL oftetrahydrofuran and 18 mL of trietylamine were added thereto, and thismixture was stirred for 20 hours at the room temperature to be reacted.After the reaction, the reaction solution was washed with a 3 wt %hydrochloride acid solution, an organic layer and an aqueous layer wereseparated. After the aqueous layer was extracted by ethyl acetate, theextract combined with the organic layer was washed with a sodiumcarbonate solution and saturated saline, in that order. Then, theorganic layer was dried with magnesium sulfate. The mixture of theorganic layer and magnesium sulfate was filtered through celite,florisil, and alumina. A solid that was obtained by concentrating thefiltrate was washed with hexane, whereby 19 g of a solid of1-(4-bromophenyl)-2-phenylacetylene that is an object was obtained inthe yield of 74% (Synthesis Scheme (n-1)).

(2) Synthesis of 4-bromobenzyle

19 g (74 mmol) of 1-(4-bromophenyl)-2-phenylacetylene, 9.4 g (37 mmol)of iodine, and 200 mL of dimethyl sulfoxide were put into a 500 mL threeneck flask and stirred for 4 hours at 155° C. to be reacted. After thereaction, the reaction mixture was cooled, and then, a 3 wt % sodiumthiosulfate solution was added thereto. This mixture was stirred for 1hour at the room temperature. Ethyl acetate was added to this mixture,and the mixture was washed with 1N diluted hydrochloric acid, a sodiumhydrogen carbonate solution, and saturated saline to separate an organiclayer and an aqueous layer. The organic layer was dried with magnesiumsulfate, and the mixture of the organic layer and magnesium sulfate wasfiltered. A solid that was obtained by concentrating the filtrate waswashed with hexane that was cooled with ice, whereby 15 g of a solid of4-bromobenzyl that is an object was obtained in the yield of 58%(Synthesis Scheme (n-2)).

(3) Synthesis of 1PPPr

3.0 g (1.0 mmol) of 4-bromobenzyl and 2.2 g (1.0 mmol) ofmeso-diphenylethylendiamine were put into a 500 mL three neck flask, and100 mL of ethanol was added thereto. This mixture was heated and stirredfor 5 hours at 80° C. to be reacted. After the reaction, the reactionsolution was concentrated, and 1.1 g of manganese dioxide and 100 mL ofchloroform were added thereto. Then, the reaction solution was furtherheated and stirred for 1 hour at 80° C. to be reacted. Thereafter, waterwas added to the reaction solution and washed, and an organic layer andan aqueous layer were separated. The organic layer was filtered throughcelite, and the filtrate was concentrated. Then, an obtained object wasre-crystallized with a mixed solvent of chloroform and hexane, whereby2.1 g of a light brown powder solid of 1PPPr that is an object wasobtained in the yield of 45% (Synthesis Scheme (n-3)).

[Step 2: Synthesis Method of YGA1PPPr]

1PPPr (2.2 mmol), 0.72 g (2.2 mmol) of YGA, and 0.3 g (3.1 mmol) ofsodium-tert-butoxide were put into a 100 mL three neck flask. Afternitrogen was substituted for the content of the flask, 20 mL of tolueneand 0.10 mL of a hexane solution (10 wt %) of tri-tert-butylphosphinewere added. Then, nitrogen was substituted for the content of the flaskagain, and 0.10 g (0.2 mmol) of bis(dibenzylideneacetone)palladium(0)were added thereto. This mixture was heated and stirred for 5 hours at80° C. to be reacted. After the reaction, toluene was added to thereaction mixture and filtered through celite, florisil, and alumina.After the filtrate was washed with water, an organic layer and anaqueous layer were separated, the organic layer was dried with magnesiumsulfate, and filtration was performed. A solid that was obtained byconcentrating the filtrate was re-crystallized with a mixed solvent ofchloroform and hexane, whereby 0.90 g of a light yellow powder solid ofYGA1PPPr that is an object was obtained in the yield of 58% (SynthesisScheme (n-4)).

An analysis result by a proton nuclear magnetic resonance method(¹H-NMR) of YGAPPPr is shown below. As a reference substance, TMS wasused.

¹H-NMR (300 MHz, CDCl₃); δ=7.07-7.17 (m, 3H), δ=7.19-7.51 (m, 23H),δ=7.53-7.82 (m, 8H), δ=8.14 (d, J=7.3, 2H)

FIGS. 51A and 51B each show a ¹H-NMR chart of YGA1PPPr. FIG. 51B is anenlarged chart of a range of 6.5 to 8.5 ppm of the chart of FIG. 51A.

FIG. 52 shows an absorption spectrum and an emission spectrum in a statewhere YGA1PPPr is dissolved in a toluene solution. Theultraviolet-visible spectrophotometer (V-550, manufactured by JASCOCorporation) was used for the measurement. In FIG. 52, the horizontalaxis represents a wavelength (nm) and the vertical axis representsintensity (arbitrary unit). Further, in FIG. 52, a line (a) indicatesthe absorption spectrum whereas a line (b) indicates the emissionspectrum (376 nm of an excited wavelength).

This application is based on Japanese Patent Application serial no.2005-378811 filed in Japan Patent Office on Dec. 28, 2005, the entirecontents of which are hereby incorporated by reference.

What is claimed is:
 1. A pyrazine derivative represented by a generalformula (g-1),

wherein R¹ and R² separately represents any one of an unsubstitutedphenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, anaphthyl group, a 2-naphthyl group, an unsubstituted9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group;wherein R³ represents any one of a hydrogen atom, an alkyl group, and anunsubstituted aryl group; wherein A represents a substituent representedby any one of a general formula (a-1), a general formula (a-2), ageneral formula (a-3), and a general formula (a-4); wherein R⁴represents an alkyl group or an aryl group; wherein R⁵, R⁶, and R⁷separately represents any one of a hydrogen atom, an alkyl group, and anaryl group; wherein Ar¹, Ar², Ar³, Ar⁴, Ar⁵, Ar⁶, and Ar⁷ separatelyrepresents an aryl group; wherein α represents an arylene group, andwherein the unsubstituted aryl group of R³ is any one of a phenyl group,an o-tolyl group, a m-tolyl group, a p-tolyl group, a napthly group, a2-naphthyl group, a 4-biphenyl group, a 3-biphenyl group, a 2-biphenylgroup, a 9,9-dimethylfluorene-2-yl group, a spiro-9,9′-bifluorene-2-ylgroup.
 2. A pyrazine derivative represented by a general formula (g-3),

wherein R¹ and R² separately represents any one of an unsubstitutedphenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, anaphthyl group, a 2-naphthyl group, an unsubstituted9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group;wherein R³ represents any one of a hydrogen atom, an alkyl group, and anunsubstituted aryl group; wherein Ar¹ and Ar² separately represents anyone of a phenyl group, a 1-naphthyl group, a 2-naphthyl group, a2-biphenyl group, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,and wherein the unsubstituted aryl group of R³ is any one of a phenylgroup, an o-tolyl group, a m-tolyl group, a p-tolyl group, a napthlygroup, a 2-naphthyl group, a 4-biphenyl group, a 3-biphenyl group, a2-biphenyl group, a 9,9-dimethylfluorene-2-yl group, aspiro-9,9′-bifluorene-2-yl group.
 3. A pyrazine derivative representedby a general formula (g-4),

wherein R¹ and R² separately represents any one of an unsubstitutedphenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, anaphthyl group, a 2-naphthyl group, an unsubstituted9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group;wherein R³ represents any one of a hydrogen atom, an alkyl group, and anunsubstituted aryl group; wherein Ar^(a), Ar⁴, and Ar^(y) separatelyrepresents an aryl group, and wherein the unsubstituted aryl group of R³is any one of a phenyl group, an o-tolyl group, a m-tolyl group, ap-tolyl group, a napthly group, a 2-naphthyl group, a 4-biphenyl group,a 3-biphenyl group, a 2-biphenyl group, a 9,9-dimethylfluorene-2-ylgroup, a spiro-9,9′-bifluorene-2-yl group.
 4. A pyrazine derivativerepresented by a general formula (g-6),

wherein R¹ and R² separately represents any one of an unsubstitutedphenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, anaphthyl group, a 2-naphthyl group, an unsubstituted9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group;wherein R⁴ represents any one of a hydrogen atom, an alkyl group, and anaryl group; wherein R³ represents any one of a hydrogen atom, an alkylgroup and an unsubstituted aryl group; wherein Ar⁶ represents any one ofa phenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-biphenylgroup, a 3-biphenyl group, a 4-biphenyl group, a9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group,and wherein the unsubstituted aryl group of R³ is any one of a phenylgroup, an o-tolyl group, a m-tolyl group, a p-tolyl group, a napthlygroup, a 2-naphthyl group, a 4-biphenyl group, a 3-biphenyl group, a2-biphenyl group, a 9,9-dimethylfluorene-2-yl group, aspiro-9,9′-bifluorene-2-yl group.
 5. A pyrazine derivative representedby a general formula (g-7),

wherein R¹ and R² separately represents any one of an unsubstitutedphenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, anaphthyl group, a 2-naphthyl group, an unsubstituted9,9-dimethylfluorene-2-yl group, and a spiro-9,9′-bifluorene-2-yl group;wherein R³ represents any one of a hydrogen atom, an alkyl group and anunsubstituted aryl group; wherein R⁶ and R⁷ separately represents anyone of a hydrogen atom, an alkyl group, and an aryl group; wherein Ar⁷represents an aryl group, and wherein the unsubstituted aryl group of R³is any one of a phenyl group, an o-tolyl group, a m-tolyl group, ap-tolyl group, a napthly group, a 2-naphthyl group, a 4-biphenyl group,a 3-biphenyl group, a 2-biphenyl group, a 9,9-dimethylfluorene-2-ylgroup, a spiro-9,9′-bifluorene-2-yl group.
 6. A light emitting elementcomprising the pyrazine derivative according to claim
 1. 7. A lightemitting element comprising the pyrazine derivative according to claim2.
 8. A light emitting element comprising the pyrazine derivativeaccording to claim
 3. 9. A light emitting element comprising thepyrazine derivative according to claim
 4. 10. A light emitting elementcomprising the pyrazine derivative according to claim
 5. 11. A lightemitting element according to claim 6, wherein the light emittingelement comprises a light emitting compound.
 12. A light emittingelement according to claim 7, wherein the light emitting elementcomprises a light emitting compound.
 13. A light emitting elementaccording to claim 8, wherein the light emitting element comprises alight emitting compound.
 14. A light emitting element according to claim9, wherein the light emitting element comprises a light emittingcompound.
 15. A light emitting element according to claim 10, whereinthe light emitting element comprises a light emitting compound.
 16. Thepyrazine derivative according to claim 1, wherein the pyrazinederivative is represented by formula (s-88)


17. A pyrazine derivative represented by any one of formulae (s-9),(s-13), (s-14), (s-16), (s-53), (s-77), (s-102,) and (s-103)